T.ihr^ 


June   12,   1929 


Mr.  George  v. .  Hawley,  CiTll  Engineer 
2409  College  -70. 
flariceloy 


Dear  Mr.  Hawley  » 

Professor  1.  F.  Lnngelier  hat  transmitted 
to  me  your  gift  of  the  boo*  "Filtration  of  Bivar  Waters'*  by 
J.  P.  Kirfcwood,  1869. 

This  historical  volume  will  be  suitably 
inscribed  and  placed  in  the  Engineering  Library  of  toe 
University.  We  prise  tnis  accession  and  thank  you  for  it. 
With  appreciation, 

Tery  truly  yours, 


Dean,  College  of  Civil,<ngineering 


DEPARTMENT  OF   CIVIL   ENGINEERING 


Berkeley,         June  11.   1929 


To:     Professor  Charles    Derleth,   Jr.  , 

De  an,   College   of  Civil  Engineering. 
Subject: 


Dear  Professor  Derleth: 

The  accompanying  volume  FILTRATION  OF  RIVER  WATERS  AS  PRACTISED 
IN  EUROPE,  being  a  report  to  the  Board  of  Water  Commissioners  of  the  City 
of  St.  Louis  by  James  P.  Kirkwood,  Civil  Engineer,  and  dated  1869  has 


been  presented  as   a  gift  to  our   department  by  Mr.   George  Hawley,    Civil 

A 

Engineer,  2409  College  Avenue,  Berkeley,  California. 

This  volume  is  of  considerable  historical  interest  and  I  consider 
it  an  important  addition  to  our  library. 

Very  truly  yours, 


W.F. 


elier. 


UNIVERSITY  OF   CALIFORNIA— (Letterhead  for  interdepartmental  use). 


or 

ORFARTMENT  OF  CIVIL  ENGINEER!!** 
BERKELEY,  CALIFORNIA1 


EEPOET 


ON   THE 


FILTRATION  OF  RIVER  WATERS, 


FOR  THE  SUPPLY  OF  CITIES, 

AS    PRACTISED,    IN    EUROPE, 


MADE   TO   THE 


BOARD    OF    WATER    COMMISSIONERS 


OF   THE 


CITY    OF   ST.    LOUIS. 

BY 

JAMES  P.  KIBKWOOD, 

CIVIL  ENGINEER. 

PUBLISHED    BY    PERMISSION  OF    THE    BOARD. 


X  3Li  Ij  TJ  S  T  FL  _A.  T  E3  ID     IB  "S"     T  H  II=L  T1  -y     E  DST  O-  FL  j^.  "V 1 3ST  O  S . 


NEW   YOEK: 

D.    VAN     NOSTRAND,    PUBLISHER, 

23  MUBBAT  STBEET  AND  27  WABBEN  STBEET  (up  BTAIBS). 
LONDON:    TRUBNER   &  CO. 

1869. 


UNIVERSITY  CF 
OSPARTMENT  OF  CIVH- 

BERKELEY.  CALIFORNIA 


ix 


iSngiaeering* 
Entered  according  to  Act  of  Congress,  in  the  year  1869,  by 

D.    VAN    NOSTEAND, 
in  the  Clerk's  Office  of  the  District  Court  of  the  United  States,  for  the  Southern  District  of  New  York. 


CONTENTS. 


NOB.  OF  ACCOMPANYING  PiQB 

PLATES. 


I.  and  H 

Report  on  Filtration  

6 

m. 

.  .  .  London  Works,  General  

21 

IV. 

.Chelsea  Water  Works  and  Filters  

27 

V. 

....Lambeth            "                 "          

34 

VI.  and  VIL 

Southwark  and  Vauxhall  Water  Works  and  Filters  

40 

vrn.      >•  . 

Grand  Junction                                                               

48 

IX. 

....West  Middlesex                            "                   "          

56 

X. 

....New  River                                     "                   "          

62 

XI. 

..  .East  London                                                                 

73 

xn. 

....Leicester                                       "                   "          

82 

xrn. 

....York                                              "                   "          

,  85 

XIV. 

....  Liverpool                                                                          

,  89 

XV. 

....Edinburgh                                      "                    "           

95 

XVI. 

....Dublin                                             "                    "           

103 

xvn. 

.Perth  Water  Works  and  Filtering  Gallery  

108 

xvm. 

Berlin            "            and  Filters  

Ill 

XIX, 

.  .  .  Hamburgh    "            and  Reservoirs  

116 

XX. 

.  Altona           "            and  Filters  

120 

XXI. 

Tours             "            and  Filtering  Canal  

124 

XXII. 

....  Angers           "            and  Filtering  Galleries  

128 

xxm. 

Nantes           "            and  Filters  

133 

XXIV. 

....Lyons            "            and  Filtering  Galleries  

137 

XXV. 

Toulouse        "            and        "              "        

143 

XXVI.  and  XXVU. 

Marseilles      "            and  Filters  

148 

xxvm. 

....  Genoa            "            and  Filtering  Galleries  

152 

XXIX.  and  XXX. 

Leghorn        "            and  Cisterns  

155 

Wakefield      "            and  Filters  

159 

APPENDIX  : 

Instructions : 165 

Table  of  Equivalents  of  Measures 167 

London  Pumping  Engines  Tabulated 168 

Boilers  of  "  ...  174 


793286 


REPORT. 


To  THE  BOARD  OF  WATER  COMMISSIONERS 

OF  THE  CITY  OF  ST.  Louis.     GEO.  K.  BUDD,  President. 

GENTLEMEN  ;   In  obedience  to  instructions   received  from   the  Board   of 

,1  have   visited 
ce  there  for  the 

.„    T  L  ii     *  11     •  these  are  made 

The  reader  will  please  correct  the  following  errata : 

Page  70,  line  4,  for  >th>us  read  about.  )rn   jn  J^a]y  .  of 

"    103,    "    7,  for  polltiuons  read  pollutions.  ince  .  of  gerljn 

"    122,    "  26,  for  basin  (c)  read  basin  (e).  Leicester   York 
"    131,    "  22,  for  (6.50  metres)  read  (0.50  metres). 

"    161,    "  10,  for  the  Thames  or  the  sea  read  the  Thames  or  the  Lea.  filtration  in  use 

time  than  I  had 

_  ^^^      fc  all  the  details 

and  statistics  which  were  desirable,  without,  a  larger  expenditure  of  time  and 
money  than  your  instructions,  however  liberally  construed,  would  have  war- 
ranted.    What  may  be  wanting,  however,  in  the  description  of  one  place  will 
generally  be  found  in  another.     No  one  but  the  superintendent  or  engineer  of 
each  work,  who  had  watched  the  process  of  filtration  from  year  to  year,  could 
give  minutely  all  the  experience  which  each  place  learns  for  itself.     The  process, 
however,  unless  where  the  areas  wore  incommensurate  with  the  service,  was  in 
England  everywhere  successful.     The   conditions  were  simple,  well  recognized, 
and  easily  understood ;  and  when,  as  in  two  instances  particularly,  they  were 
violated,  it  was  but  temporarily— the  increase  of  area  required  being  acknowl- 
edged, and  being  about  to  be  corrected.* 


*  January,  18G9.     At  each  of  these  places  the  enlargement  of  the  filtering  area  has  since  been  made. 


REPORT. 


To  THE  BOARD  OF  WATER  COMMISSIONERS 

OF  THE  CITY  OF  ST.  Louis.     GEO.  K.  BUDD,  President. 

GENTLEMEN  :  In  obedience  to  instructions  received  from  the  Board  of 
Water  Commissioners  in  December,  1865  (see  Appendix),  I  have  visited 
Europe  for  the  purpose  of  understanding  the  modes  in  practice  there  for  the 
nitration  or  clarification  on  a  large  scale  of  river  waters,  where  these  are  made 
use  of  for  domestic  purposes  in  the  supply  of  cities. 

To  this  end  I  have  visited  the  cities  of  Genoa,  and  Leghorn,  in  Italy  ;  of 
Marseilles,  Toulouse,  Lyons,  Tours,  Angers,  and  Nantes  in  France  ;  of  Berlin, 
Hamburgh,  and  Altona  in  North  Germany,  and  of  London,  Leicester,  York, 
Liverpool,  Edinburgh,  Perth,  and  Dublin  in  Great  Britain. 

I  submit  herewith  statements  descriptive  of  the  modes  of  filtration  in  use 
at  each  of  these  places. 

The  obtaining  of  this  information  has  occupied  much  more  time  than  I  had 
anticipated.  In  many  places  it  was  found  impossible  to  get  at  all  the  details 
and  statistics  which  were  desirable,  without  a  larger  expenditure  of  time  and 
money  than  your  instructions,  however  liberally  construed,  would  have  war- 
ranted. What  may  be  wanting,  however,  in  the  description  of  one  place  will 
generally  be  found  in  another.  No  one  but  the  superintendent  or  engineer  of 
each  work,  who  had  watched  the  process  of  filtration  from  year  to  year,  could 
give  minutely  all  the  experience  which  each  place  learns  for  itself.  The  process, 
however,  unless  where  the  areas  were  incommensurate  with  the  service,  was  in 
England  everywhere  successful.  The  conditions  were  simple,  well  recognized, 
and  easily  understood ;  and  when,  as  in  two  instances  particularly,  they  were 
violated,  it  was  but  temporarily — the  increase  of  area  required  being  acknowl- 
edged, and  being  about  to  be  corrected.* 

*  January,  18G9.     At  each  of  these  places  the  enlargement  of  the  filtering  area  has  since  been  made. 


0  REPORT   ON    THE 

In  France,  while  what  is  called  the  natural  filter  is  successful,  the  arti- 
ficial filter  is  usually  a  failure,  for  reasons  which  are  sufficiently  explained  in  the 
descriptions  of  the  several  places. 

In  England,  where  the  rivers  rarely  carry  as  much  sediment  as  the  Missis- 

.  'sipps,:  except  in  floods,  I  found  the  arrangements  for  filtration  very  general  and 

;  •  -.very  Jnanageable,  and  that,   so  far  as  my  knowledge  extends,  wherever  a  city 

derived  its  supply  from  river  or  stream,  unless  where  large  storage  reservoirs 

intervened,  filter  beds  were  used  as  a  matter  of  course,  to  render  the  water 

in  every  case  as  unobjectionable  and  satisfactory  to    the  consumer  as  might 

be  practicable. 

In  England  and  France,  where  the  winters  are  usually  mild,  the  ice  seldom 
forms  so  thick  as  to  require  any  extra  attention  on  the  filtering  basins.  I  visited 
Northern  Germany,  where  the  climate  is  as  severe  as  our  own,  to  understand 
whether  the  formation  of  thick  ice  impeded  or  interrupted  the  filtering  process. 

In  the  description  of  each  place,*  while  the  special  object  is  to  give  an 
account  of  its  filtering  works,  I  have  noted  such  other  information  as  incident- 
ally came  within  my  reach,  in  order  that  the  general  scheme  of  each  place 
might  be  understood. 

Instead  of  giving  a  synopsis  illustrative  of  the  varying  experience  of  the 
different  places  described,  it  will  be  more  useful  probably  to  explain  the  prin- 
ciples in  practice,  which  govern  the  construction  and  operation  of  filter  beds 
in  England  and  elsewhere. 

The  accompanying  sketches  of  a  filter  bed  suitable  for  St.  Louis,  will  serve 
to  illustrate  the  details  of  this  practice. 

It  will  be  obvious,  however,  that  the  pertinency  of  what  I  may  say  can- 
not be  judged  of  without  that  kind  of  preliminary  information  which  the  state- 
ments referred  to  are  intended  to  convey. 

We  are  accustomed  here  to  consider  the  filtering  arrangements  on  Euro- 
pean works,  as  having  in  view  simply  the  removal  of  the  fine  sediments  which 
discolor  river  waters  ;  but  the  filter  bed  equally  intercepts  and  removes  the 
fine  vegetable  fibres  and  the  minute  organisms,  vegetable  or  animal,  which  in 
all  river  waters  prevail  more  or  less  during  certain  of  the  summer  months. 
The  removal  of  this  class  of  impurities  is  getting  to  be  considered  in  England, 
and  elsewhere,  as  of  as  much  importance  as  the  removal  of  the  sedimentary 
uncleanness  which  is  more  apparent.  During  certain  of  the  summer  months, 
when  the  rivers  usually  carry  but  little  sediment,  this  forms  the  chief  duty  of 
the  filter  beds.  The  surface  of  the  sand  becomes  occasionally  as  much 

*  Since  this  report  was  written,  the  London  journal  called  "Engineering"  has  published  descriptions  of  the 
London  Water  Works,  in  which  will  be  found  minute  descriptions  of  several  of  the  London  pumping  engines. 
The  "Encyclopedia  Britaunica,"  "  Bourne's  Specimens,"  and  "The  Engineer,"  may  also  be  consulted  for  similar 
details. 


FILTRATION    OF   RIVER   WATERS.  7 

impeded  then  with  this  matter  as  with  the  earthy  sediments  which  more 
usually  clog  it,  and  it  is  of  a  nature  to  taint  the  water  under  certain  condi- 
tions more  ofi'ensively  than,  the  other.  The  sand  filters  are  therefore  con- 
sidered very  important  instruments  of  purification  in  this  relation.  They 
become,  indeed,  screens  of  the  greatest  delicacy,  intercepting  all  material 
impurities,  not  the  least  of  which  are  the  very  small  fish  with  which  all 
waters  are  crowded  at  certain  seasons.  Most  of  the  European  rivers,  how- 
ever, pass  through  lands  where  manure  is  used  more  extensively,  and  where 
a  higher  state  of  cultivation  prevails  than  on  the  lands  bordering  our  West- 
ern rivers  ;  and  where  also  a  denser  population  usually  exists.  Our  rivers, 
therefore,  will  not  probably  for  a  long  time  carry  at  any  time  the  same 
amount  of  organic  matter  in  suspension. 

In  some  of  the  places  visited  by  me,  what  is  called  the  natural  filter  is 
in  successful  use  ;  I  will  refer  to  this  again,  and  confine  myself  first  to  the 
artificial  filter. 

The  filter  bed  was  designed  to  get  rapidly  rid  of  that  very  light  portion  of 
the  sediment  carrried  by  river  waters,  which  takes  some  time  (a  fortnight  or 
more)  to  subside  under  ordinary  circumstances.  This  clayey  discoloration, 
though  trifling  in  weight,  renders  the  water  very  objectionable  in  appearance, 
very  objectionable  in  its  application  to  any  of  the  arts  or  manufactures,  and 
no  acquisition  certainly  either  as  regards  health  or  cleanliness  ;  although  cus- 
tom, as  on  the  Western  rivers,  may  reconcile  persons  to  its  presence,  especially 
when  its  absence  is  associated,  as  there,  with  the  hard  and  unpalatable  waters 
of  the  lime-stone  springs.  That  portion  of  the  sediment  which,  from  its 
greater  weight,  subsides  rapidly,  say  within  twenty-four  hours,  can  be  more 
economically  got  rid  of  in  subsiding  reservoirs.  The  successful  use  of  the 
filter  bed  presupposes  the  preparation  of  the  water  in  a  subsiding  reservoir. 
Wherever  the  attempt  has  been  made  to  use  filter  beds  without  that  prelimi- 
nary aid,  they  have  either  failed  altogether,  as  in  France,  or  rendered  the 
water  but  partially  clarified,  as  in  one  of  the  London  -works.  On  the  London 
works  the  aid  of  subsiding  reservoirs  is  being  more  and  more  availed  of  of  late 
years,  both  as  rendering  the  filtering  process  more  economical,  which  they 
s'iem  to  have  been  slow  to  perceive,  and  as  a  necessary  auxiliary  in  time  of 
Hood,  to  the  efficiency  of  the  other.  They  have  become  besides,  valuable 
expedients,  especially  on  the  Lea,  for  the  storage  of  water.  In  some  places 
as  at  Liverpool,  Leicester,  Edinburgh,  and  Dublin,  the  large  valley  reservoirs 
required  for  compensation  and  flood  storage,  perform  for  the  filter  beds  the 
functions  of  a  subsiding  reservoir. 

I  will  refer  again  to  the  size  and  arrangement  of  these. 

The  materials  used  for  filtration  on  a  large  scale  are  very  simple.  They  are 
sand,  gravel,  and  broken  stone  or  shingle — the  depth  of  the  whole  varying  from 


8  REPORT   ON    THE 

five  to  six  and  one-half  feet  ;  a  layer  of  shells  has  sometimes  been  used, 
placed  within  the  stratum  of  gravel,  but  this  is  not  found  essential,  and  is  now 
generally  omitted. 

It  will  be  convenient  to  consider  here  the  most  appropriate  size  for  a  filter 
bed  before  giving  the  arrangement  and  thickness  of  its  materials.  The  sizes  in 
practice  will  be  found  to  be  very  variable,  and  seemingly  to  have  followed  no 
regular  standard.  The  first  filter  beds  at  Chelsea  proved  inconveniently  large, 
and  have  since  in  practice  been  divided.  The  new  filter  beds  at  Stoke  Newing- 
ton  (London),  the  filter  beds  at  Liverpool,  and  those  now  under  construction  at 
Dublin,  are  fair  specimens  of  modern  practice,  as  applied  to  large  cities.  For 
small  cities  it  is  found  convenient  to  make  the  dimensions  proportionally 
smaller. 

The  areas  of  these  are  45,000,  30,000  and  22,550  square  feet  each,  respect- 
ively. Their  forms  are  rectangular,  300  X  150,  300  X  100,  and  205  X  110. 

At  Stoke  Newington,  with  a  delivery  of  12,000,000  imperial  gallons  daily, 
there  are  5  filter  beds  in  use  now,  and  two  projected,  making  7  in  all  when 
complete. 

At  Liverpool  there  are  6  now,  for  a  delivery  of  9,000,000  to  12,000,000 
imperial  gallons. 

At  Dublin,  for  an  assumed  delivery  of  12,000,000  imperial  gallons,  there 
are  7  filter  beds  in  process  of  construction. 

Each  filter  bed,  at  short  intervals  varying  with  the  condition  of  the  water, 
must  have  the  deposit  which  accumulates  on  the  surface  of1  the  sand  cleaned  off 
or  removed,  and  while  any  one  is  undergoing  this  cleansing  process,  the  other 
remaining  filters  must  be  competent  to  deliver  the  required  supply  without 
overstraining  their  functions.  If,  then,  there  are  six  filters,  five  of  them  must  be 
competent  to  the  full  duties  of  the  service,  and  if  eight  filters,  seven  of  them 
must  be  competent  to  this  duty,  on  the  supposition  always  that  not  more  than 
one  filter  will  at  any  time  be  oft'  duty.  Should  the  circumstances  in  effect  render 
two  unserviceable,  the  remainder  must  have  area  enough  to  meet  the  require- 
ments of  the  case. 

We  see,  then,  that  the  smaller  the  filter  beds— with  the  condition, 
however,  that  not  more  than  one  shall  be  off  duty  at  a  time  —  the 
smaller  will  be  the  total  area  of  filtering  surface  required  for  the  particular 
duty.  The  materials  available  for  construction,  and  their  cost,  will  also 
measurably  influence  the  dimensions  to  be  adopted,  and  it  must  always 
be  borne  in  mind  that  although  there  may  be  but  one  filter  off  duty, 
it  will  frequently  happen  that  another  is  nearly  unserviceable.  It  is, 
therefore,  found  best  to  give  a  liberal  area  of  filtering  surface,  to  be  prepared 
for  all  the  contingencies  of  the  service.  For  a  city  of  the  population  and  pros- 
pects of  St.  Louis,  I  will  for  the  present  assume  200  X  150  as  convenient  dimen- 


FILTKATION   OF   RIVER   WATERS.  9 

sions,  giving  an  effective  area  of  37,450  square  feet  for  each  filter  bed.  See 
Plates  1  and  2. 

The  bottom  of  the  filter  bed  is  prepared  to  suit  the  circumstances  of  its  position. 
It  must  be  made  practically  water-tight.  This  is  sometimes  insured  by  laying 
concrete  on  the  bottom  (a  Plate  2),  but  quite  as  often  by  a  layer  of  hard  clay 
puddle  18  to  24  inches  thick,  over  which  a  flooring  of  brick  is  laid  ;  where  the 
ground  is  more  than  usually  bad,  both  the  clay  and  the  concrete  may  be  used 
with  advantage  ;  when  concrete  is  used  the  brick  paving  is  not  essential.  Upon 
this  flooring  a  central  drain  (b)  running  lengthwise  is  laid,  with  which  are  con- 
nected on  either  side  small  tubular  drains  (c)  of  6  to  9  inches  diameter,  pre- 
pared for  this  purpose,  the  sides  being  pierced  with  holes  to  facilitate  the 
entrance  of  the  water.  These  side  drains  are  laid  nearly  at  right  angles  to  the 
central  drain,  and  from  8  to  12  feet  apart.  The  central  drain  referred  to  as 
arranged  in  Plate  2,  and  as  in  use  on  many  of  the  London  niters,  is  a  double 
drain ,  performing  two  offices— the  lower  part  (b),  which  is  covered,  gathering 
the  filtered  water,  and  the  upper  part  (d),  which  is  open,  delivering  the  unfiltered 
water  upon  the  sand,  when  refilling  a  filter  bed  immediately  after  cleansing, 
and  in  use  then  only  for  that  special  purpose.  This  central  drain  is  sometimes 
of  brick,  and  sometimes  of  stone  covered  with  stone  flagging,  the  side  walls  of  the 
lowest  twelve  inches  of  the  drain  being  in  either  case  laid  dry  ;  the  water-way 
for  this  size  of  filter  should  not  be  less  than  30  inches  wide  by  15  inches  of 
height. 

A  little  reflection  will  show  that  the  lateral  drains  can  hardly  be  placed  too 
close  together,  for  it  is  desirable  that  the  filtered  water  should  flow  to  the  col- 
lecting drains  with  as  slow  a  velocity  as  possible ;  and  the  further  these  drains 
are  apart,  the  greater  must  be  the  amount  of  water  running  through  each  drain. 

In  the  latest  constructed  filter  beds  of  the  New  River  Works  at  Stoke  Newing- 
ton,  the  lateral  pipe  drains  are  dispensed  with,  and  over  the  brick  flooring,  dry 
brick  are  laid  instead  ;  forming  a  series  of  small  drains  not  more  than  six  inches 
apart  from  centre  to  centre.  The  filtered  water  finds  its  way  into  these  through 
the  open  joints  of  the  bricks.  This  forms  the  most  perfect  arrangement  for 
collection  that  I  have  met  with  ;  but  it  is  also,  probably,  the  most  expensive. 
These  small  drains  deliver  there  into  two  central  drains. 

This  drainage  skeleton  rests  on  the  base  of  the  filter  bed,  and  becomes  the 
means  provided  to  collect  the  filtered  water  and  deliver  it  to  the  outer  passages 
or  wells.  Upon  the  flooring  of  the  filter  beds,  and  covering  the  gathering  drains 
as  well  as  filling  up  the  intervening  spaces,  a  layer  of  broken  stones  is  laid, 
large  shingle  or  quarry  spauls  (e). 

The  stone  should  not  be  larger  than  will  pass  through  a  4-inch  ring,  nor  less 
than  will  pass  through  a  2-inch  ring,  and  they  must  be  clean  and  free  from 
earth  or  quarry  rubbish. 


10  REPORT    ON    THE 

The  shingle  so  called  is  obtained  in  England  from  coarse  gravel  or  beach 
deposits,  and  is  screened  to  the  size  wanted. 

This  layer  of  broken  stone  wants  to  be  24  inches  thick  to  cover  efficiently 
the  pipe  drains.  Upon  this  layer  of  stone  properly  levelled  off,  from  18  to  24 
inches  of  gravel  is  laid  (/),  say  18  inches.  This  gravel  is  usually  screened  into 
two  or  three  sizes, — the  larger  of  walnut  size,  the  next  of  the  size  of  a  hazel  nut, 
and  the  third  between  that  and  pea  size.  The  largest  size  lies  upon  the  broken 
stone,  the  smallest  size  at  the  top,  the  layers  six  inches  thick  each.  Over  this 
gravel  there  wants  to  be  laid  not  less  than  30  inches  of  fine  sharp  sand  (g). 
The  sand  to  be  screened  to  insure  the  requisite  degree  of  fineness  and  uniform- 
ity. The  lower  12  inches  may  be  a  little  coarser  than  the  upper  stratum  of  18 
inches,  but  it  is  important  that  the  two  layers  should  be  of  uniform  fineness 
and  quality  throughout,  otherwise  there  will  be  danger  of  the  water  passing 
through  more  rapidly  at  one  point  than  another.  The  whole  depth  of  these 
materials  amounts  to  Jive  feet  eight  inches, — a  depth  which  will  appear  at  first 
sight  unnecessarily  great,  since  we  know  that  the  upper  stratum  of  sand  per- 
forms apparently  the  whole  duty  of  cleansing  the  water.  The  different  degrees 
of  fineness  in  the  materials  beneath  the  sand  and  their  several  thicknesses, 
were  intended  first  to  prevent  the  fine  sand  from  following  the  water  down- 
ward into  the  drains,  and  next  to  insure  the  presence  of  such  a  body  of  clean 
water  below  the  surface  of  the  filter,  as  would  penetrate  the  numerous  joints 
and  openings  of  the  drains,  and  keep  them  full,  without  creating  anywhere 
currents  or  veins  of  water  of  any  perceptible  difference  of  velocity. 

With  the  drains  much  nearer  to  the  body  of  the  sand,  it  will  be  understood 
that  the  tendency  of  the  water  would  be  to  flow  through  the  filtering  material 
more  rapidly  just  over  the  pipe  than  at  5  feet  on  either  side  of  it.  The  dis- 
tance through  which  it  had  to  travel  might  be  so  short  as  to  induce  its  concen- 
tration. The  low  velocity  at  which  the  water  flows  through  the  filter,  the 
uniformity  of  fineness  in  the  sand,  and  the  distance  of  the  collecting  drains  from 
its  surface,  all  work  together  to  produce  that  regularity  of  action  over  the 
entire  filter  bed  upon  which  its  perfection  depends.  The  large  gravel  and 
the  broken  stone  covering  the  lateral  drains,  presents  in  fact  by  the  voids  or 
spaces  existing  in  such  material,  an  innumerable  collection  of  crooked  tubes 
conveying  the  water  in  as  many  threads  to  the  collecting  drains,  and  rendering 
as  well  its  concentration  impracticable. 

All  the  clear  water  underlying  the  surface  of  the  earth,  from  which  our 
springs  and  wells  derive  their  supplies,  has  been  filtered  into  the  clearness  in 
which  it  is  found,  by  passing  through  earthen  strata,  where  the  muddy  impu- 
rities which  it  held  on  the  surface  after  heavy  rains,  have  been  intercepted  and 
separated  by  a  process  precisely  similar  to  that  of  the  sand  filter,  so  far  as  its 
limpidity  is  concerned. 


FILTRATION    OP   RIVER    WATERS.  11 

From  the  ends  of  the  pipe  drains  referred  to,  as  well  as  from  the  end 
of  the  central  drain,  small  cast-iron  pipes  (A),  of  4  inches  diameter,  rise  to 
the  surface  of  the  ground  to  enable  the  air  to  escape  while  the  water  is 
being  first  let  on  upon  the  filter  bed. 

In  England  the  sides  are  usually  paved  with  brick  or  stone  to  slopes  of 
from  1  to  1  to  2  to  1.  In  this  climate  as  in  North  Germany  the  side  walls 
would  have  to  be  vertical  on  account  of  ice  (see  Plate  2),  and  the  depth  of  the 
water  over  the  filter  beds  should  not  be  less  than  4  feet.  With  vertical  walls 
as  at  Berlin  and  Altona,  the  attendant,  with  proper  tools,  readily  keeps  the  ice 
separated  from  the  walls,  and  although  it  frequently  forms  18  inches  thick,  and 
occasionally  24  inches,  it  does  not  interfere  with  the  filtration,  nor  has  it  dam- 
aged the  side  walls,  to  which  the  floating  cake  of  ice  is  never  allowed  to 
become  attached.  The  water  of  the  river  Spree  at  Berlin,  and  of  the  Elbe  at 
Altona,  is  usually  clearer  in  winter  than  in  summer.  The  filter  beds  on  that 
account  will  operate  for  a  longer  period  during  the  winter  months  than  at 
other  times  without  being  uncovered.  At  Berlin  and  Altona,  as  I  was 
informed,  the  filtering  had  never  been  interrupted  in  winter  nor  had  the 
works  been  damaged  by  the  ice.  In  our  Western  rivers  the  winter  waters 
usually  present  the  same  character  of  greater  clearness  during  the  winter  than 
during  the  summer  months.  But  some  winters  are  exceptional  in  this  respect, 
and  during  such  winters  it  would  be  desirable  and  might  be  necessary  to 
uncover  and  clean  off,  as  in  summer,  any  filter  that  should  become,  from  an 
accumulation  of  sediment,  unserviceable.  The  proposed  roofing  in  of  the  filter 
beds,  to  defend  them  from  the  hot  suns  of  midsummer,  would  come  into  play 
here  to  defend  the  beds  on  occasion  from  frost,  and  admit  of  their  being 
uncovered  for  cleansing.  Practice  would  speedily  indicate  how  best  to  meet 
any  exceptional  difficulty  of  this  kind ;  and  what  had  succeeded  so  well  in  the 
severe  climate  of  Northern  Germany,  would  not  probably  fail  here  from  want 
of  the  required  ingenuity  or  intelligence  to  meet  the  case. 

In  the  worst  stages  of  the  English  rivers  a  filter  bed  has  to  be  cleansed 
once  a  week,  rarely  oftener. 

The  stuff,  whether  sediment  or  otherwise,  intercepted  by  the  filter,  is  found 
collected  on  the  surface  of  the  sand  ;  in  the  process  of  its  removal,  a  thin 
paring  of  sand  is  necessarily  taken  with  it,  not  exceeding  from  half  an  inch  to 
three-quarters  of  an  inch  in  thickness.  The  impurities  carried  by  the  water  are 
not  found  to  have  penetrated  the  sand.  The  paring  of  sand  is  usually  cleansed 
and  laid  aside  for  future  use,  except  when  fresh  sand  can  be  procured  at  less 
cost  than  the  washing  of  the  old  sand.  The  thickness  of  the  sand  bed  is 
allowed  to  be  reduced  by  these  repeated  parings  from  8  to  12  inches  before  it 
is  renewed. 

The  original  thickness  of  30  inches  of  sand  becomes  then  but  18  or  22 


12  REPORT    ON    THE 

inches  before  it  is  replaced  and  brought  up  to  the  original  lines.  The  renewal 
is  usually  made  once  in  six  months,  sometimes  but  once  a  year,  as  the  conve- 
vcnience  of  the  service  may  permit. 

At  each  cleansing  of  the  filter  bed  the  sand  is  loosened  by  forks  for  some  6 
to  8  inches  in  depth,  and  afterwards  raked  smoothly  over. 

The  sand  is  liable  to  pack  close  if  the  cleansing  is  too  long  delayed.  .  In 
such  case  the  weight  of  the  water  is  felt  upon  the  sand  ;  in  the  usual  state  of  the 
filter  it  is  not  so  felt. 

The  filter  bed  is  usually  filled  with  water  from  above  by  flowing  it  slowly 
upon  the  sand  either  from  one  point  in  connection  with  an  overflow  drain  (as 
in  Plate  2)  or  from  several  points  on  the  side  of  the  filter.  It  would  be  safer 
and  more  convenient  as  regards  getting  rid  of  the  air,  to  fill  it  from  below  by 
means  of  the  drains  there  ;  but  if  this  were  done  with  the  uncleaned  water  it 
would  distribute  its  impurities  all  through  the  filter.  The  filtered  water  may, 
however,  by  suitable  arrangements,  be  made  available  for  this  service.  When 
the  filter  has  been  once  filled  it  is  not  necessary  to  empty  it  entirely  at  each 
cleansing  of  its  surface. 

The  lowering  of  the  water  12  to  18  inches  below  that  surface  will  after- 
wards be  sufficient  to  admit  of  the  workmen  removing  the  crust  of  sediment  col- 
lected upon  it. 

To  insure  the  perfect  cleansing  of  the  water  by  the  filters  as  well  as  to  pre- 
vent any  disarrangement  of  the  materials  of  which  they  are  composed,  the 
velocity  of  movement  of  the  water  must  be  very  slow.  There  is  but  little 
difference  of  opinion  among  English  engineers  as  to  the  best  average  rate, 
although  in  some  places  that  rate  is  exceeded,  the  consumption  of  water  having 
in  such  cases  increased  more  rapidly  than  was  anticipated  ,  and  the  works  fallen 
temporarily  behind  the  necessities  of  the  service. 

Mr.  Charles  Greaves,  Engineer  of  the  East  London  Water  Works,  limits  this 
rate  to  an  average  of  one-half  gallon  per  minute  for  each  square  yard  of  sand 
surface,  which  is  equal  to  3s  gallons  per  hour  for  each  square  foot  of  sand 
ai-ea  of  the  filter  bed.  Mr.  James  Simpson,  Engineer  of  the  Lambeth  and  Chel- 
sea Water  Works,  who  may  be  said  to  be  the  originator  of  the  method  of  filter- 
ing now  in  such  general  use  in  England,  gave  me  as  his  opinion  that  the  filtering 
surface  should  be  predicated  on  a  rate  of  72  gallons  per  diem  for  each  square 
foot  of  sand,  which  is  equal  to  3  gallons  per  hour  per  square  foot.  Mr.  Henry 
Gill,  Engineer  of  the  Berlin  Water  Works,  considered  that  the  rate  should  not 
exceed  half  a  cubic  foot  of  water  (31  gallons)  per  hour  per  square  foot  of  sand. 
Mr.  Thomas  Duncan,  Engineer  of  the  Liverpool  Water  Works,  who  is  a  close 
observer,  gave  me  his  opinion  that  the  works  should  have  in  view  a  rate  of 
filtration  of  from  half  a  cubic  foot  (3s  gallons)  to  one-third  cubic  foot  (2T\r 
gallons)  per  hour  per  square  foot  of  sand. 


FILTRATION    OF   RIVER   WATERS. 


13 


The  gallons  mentioned  above  are  imperial  gallons.     It  will  be  convenient  to 
give  all  the  measures  in  feet,  the  various  gallon  measures  differing  considerably. 
Referred  to  feet,  the  opinions'of  these  engineers  appear  as  follows : 


RATE  OF  FILTRATION  »  CUBIC  FEET  OK  WATKR, 

PER  SlIUiRB  FOOT  OF  SiND  SURFACE. 

Per  Hour. 

Per  Diem. 

0.533 
0.480 
0*50 
0.50 

12.79 
11.52 
12.00 
12.00 

Mr  Henry  Gill                               

Mr.  Thos.  Duncan  

I  will  assume  half  a  cubic  foot  of  water  per  hour  per  square  foot  of  the  sand 
floor  as  a  fair  exponent  of  the  best  English  practice,  and  as  a  rate  which  with 
the  usual  attention  will  be  certain  to  insure  satisfactory  results.  This  rate  is 
equivalent  to  75  imperial  gallons,  or  891  United  States  gallons,  per  foot  square 
per  diem. 

When  the  flow  of  water  through  the  system  of  filters  during  the  24  hours 
cannot  be  made  uniform,  that  is  to  say,  when,  as  is  sometimes  the  case  (in  the 
absence  of  an  intermediate  clear  water  basin),  it  varies  with  the  consumption, 
being  greater  during  the  day  hours  than  during  the  night  hours,  the  combined 
area  of  the  filter  beds  in  that  case  should  be  made  to  meet  the  maximum  or 
daylight  consumption  of  the  service  per  hour. 

The  average  rate  of  half  a  cubic  foot  per  hour  pre-supposes  a  maximum  and 
a  minimum  rate,  both  of  which  have  their  working  limits.  When  the  filter  is 
clean  the  water  is  allowed  to  pass  through  more  rapidly  than  the  average 
velocity  of  six  inches  per  hour,  and  when  it  becomes  clogged  with  sediment  it 
cannot  be  made  to  pass  through  it  at  that  rate.  So  far  as  I  can  judge,  the  rate 
should  not  exceed  8.8  inches  per  hour  (110  imperial  gallons  per  square  foot) 
when  the  water  is  clean,  nor  get  below  3.2  inches  per  hour  (40  imperial  gallons 
per  square  foot)  when  it  becomes  obstructed  by  the  deposit.  Mr.  Hack,  of  the 
West  Middlesex  Water  Works,  stated  that  it  varied  on  their  filter  beds  from  11  \ 
inches  to  2.9  inches  per  hour  ;  but  these  appear  to  me  to  be  extremes,  rather 
to  be  avoided  than  copied. 

The  objection  to  the  very  low  velocity  of  2.9  inches  per  hour  may  not  be 
apparent  without  explanation.  The  most  obvious  objection  refers  to  the  work 
done  ;  the  delivery  at  that  rate  is  trifling  and  incommensurate  with  the  cost  of 
the  machine  ;  but  the  low  velocity  indicates  another  source  of  danger  growing 
out  of  the  compression  or  packing  induced  upon  the  sand  by  the  sealing  of 

2 


14  REPORT    ON    THE 

its  surface,  and  the  risk  of  this  almost  impervious  coating  being  of  unequal 
thickness,  and  of  the  water  venting  itself  unequally  at  the  thinner  spots. 

The  filtered  water  from  each  filter  bed"  should  be  delivered  into  a  small 
well  (as  at  m,  Plate  2),  whence  it  escapes  into  the  proper  conduit,  and  is  carried 
either  to  a  common  clear  water  basin,  or  directly  to  the  pumps.  The  sluices  at 
this  well  can  be  so  arranged,  by  operating  downwards  instead  of  upwards,  as  to 
adjust  the  head  of  water  actually  in  action  upon  the  filter  bed.  When  the  filter 
is  clean,  nine  inches  of  head  will  produce  the  required  flow  through  the  filtering 
material  ;  according  as  the  sediment  becomes  deposited  on  its  surface,  this  head 
has  to  be  increased  to  2  or  1\  feet,  varying  a  little  with  the  character  of  the 
sand.  If  the  head  be  allowed  to  exceed  3  feet,  it  is  because  the  surface  is  being 
rapidly  closed  ;  the  weight  of  the  water  comes  then  into  play  upon  the  sand, 
induces  the  packing  already  referred  to,  and  leads  to  the  labor  of  loosening  up 
the  material  during  the  process  of  cleansing.  Sometimes  when  this  amount  of 
head  is  exceeded,  the  pressure  leads  the  water  to  break  through  at  points 
where  some  slight  difference  in  the  material  gives  it  opportunity.  It  will  then 
flow  through  in  veins,  damaging  the  filter  bed.  Such  overstraining  of  the  filters 
is  rare.  I  observed  but  one  instance  of  it,  but  the  effect  can  readily  be  brought 
about  by  overworking  the  filters. 

The  English  filters  are  all  deficient  as  regards  any  arrangement  for  meas- 
uring the  precise  flow  from  each  filter,  or  the  precise  head  of  water  on  each 
filter  while  it  is  in  action.  A  simple  arrangement,  involving  very  little  cost, 
admits,  as  our  sketch  shows,  of  this  knowledge  being  rendered  certain  where  it 
is  now  guessed  at.  In  London,  where  the  service  of  each  company  is  effected 
by  steam  power,  the  daily  or  hourly  delivery  of  the  pumps  forms  the  measure 
of  the  amount  of  water  passing  through  the  filters.  The  engineer  knows  by 
this  means  when  the  filtering  area  is  too  small,  because  in  that  case  the  pumps 
are  insufficiently  supplied  ;  and  he  would  know  if  the  water  was  passed  through 
the  filters  too  rapidly,  by  its  want  of  that  perfect  clearness  which  an  efficient 
filtration  always  produces.  But  of  the  separate  action  of  each  individual  filter 
bed  he  is  ignorant,  except  by  guess.  The  attendant  can  see  when  the  filter  bed 
has  ceased  to  operate,  by  its  ceasing  to  pass  the  water  thrown  upon  it,  and  he 
can  see  when  it  passes  the  usual  amount  too  rapidly,  and  can  check  this  ten- 
dency by  lowering  his  stopcocks  and  allowing  the  water  to  lower  upon  the  filter 
bed  ;  but  his  judgment  may  frequently  be  in  fault  in  both  cases,  and  there 
ought  to  be  something  more  than  the  instincts  of  an  intelligent  laborer  to  regu- 
late points  of  so  much  practical  bearing  on-  the  proper  working  of  these  filter 
beds,  as  the  varying  amount  of  water  delivered  upon  them,  and  the  constantly 
varying  head  required  to  pass  that  water  under  the  changing  conditions  of  the 
sand  bed. 

The  small  well  at  the  terminus  of  the  centre  gathering  drain,  with  the  iron 


FILTRATION   OF   RIVER    WATERS.  15 

sluice  shown  there  (Plates  2  and  3)  operating  downwards,  will  enable  the  attend- 
ant to  know  at  any  time  the  head  in  action  upon  each  filter,  and  the  amount  of 
water  passing,  for  the  top  of  the  sluice  becomes  then  a  weir.  He  will  thus  learn, 
without  guessing,  when  the  delivery  of  any  filter  is  so  low  as  to  render  cleansing 
essential,  and  will  throw  it  out  of  action  and  have  it  cleansed  accordingly,  and 
he  will  learn  precisely,  as  the  sand  bed  becomes  gradually  clogged,  the  head  of 
water  under  which  it  will  continue  to  deliver  sufficiently — beyond  which  amount 
of  head  it  is  needless,  and  it  might  be  dangerous  to  go  ;  and  he  can  always  at 
the  sluice  regulate  precisely  the  amount  drawn  from  the  filter  per  hour,  so  that 
the  flow  through  it  shall  never  be  too  rapid,  nor  the  water  permitted  to  be 
imperfectly  cleansed.  He  will  learn  by  this  means,  in  fine,  what  the  safe  maxi- 
mum flow  really  is  ;  and  as  it  becomes  less  and  less  notwithstanding  the 
increased  head  produced  by  his  lowering  of  the  sluice,  he  will  ascertain  the  least 
flow  under  which  it  is  advisable  to  work  it,  and  will  know  exactly  when  to 
throw  it  off  and  prepare  it  for  cleansing. 

The  best  size  of  filter  bed  for  such  a  city  as  St.  Louis  has  been  assumed  to 
be  260  X  150,  giving  a  sand  area  of  37,440  square  feet.  This  area,  at  the  rate 
of  one-half  cubic  foot  of  water  per  hour  per  square  foot  of  bed,  gives  a  filtration 
18,720  cubic  feet  of  water  per  hour,  which  is  equivalent  to  449.280  cubic  feet, 
or  3,360,847  United  States  gallons  in  twenty-four  hours. 

To  filter  twelve  millions  of  gallons  daily,  five  filters  of  this  size  would  be 
necessary,  on  the  supposition  that  the  flow  of  water  through  four  of  them  is 
continuous  through  the  twenty-four  hours.  To  insure  this  condition  the  clear 
water  basin  should  be  large  enough  to  receive  the  water  passing  through  the 
filters  during  the  night  hours,  accumulating  it  there  for  the  day  service. 

This  clear  water  basin  need  not  be  large.  The  ability  to  store  up  one- 
third  of  the  calculated  daily  consumption  would  meet  the  case. 

I  have  very  little  information  in  regard  to  the  precise  cost  of  filtration  in 
England,  no  separate  account  being  ordinarily  kept  of  its  particular  expenses. 
At  the  Chelsea  Water  Works,  London,  the  extra  charge  for  filtering,  Mr.  Simp- 
son informed  me,  averaged  4  shillings  and  6  pence  per  annum  per  tenement. 
If  each  tenant  consumed  300  imperial  gallons  per  diem,  this  charge  would'  be 
equal  to  one  cent  (specie)  for  each  1,314  United  States  gallons.  The  charge 
probably  includes  some  profit. 

At  Liverpool,  Mr.  Duncan  found  the  cost  of  filtering  (exclusive  I  presume 
of  the  capital  invested  in  it)  to  average  nearly  £100  sterling  per  annum  for 
a  million  imperial  gallons  filtered  daily,  or  for  each  365,000,000  imperial 
gallons. 

This  is  equal  to  1.14  mills  per  thousand  United  States  gallons  or  $1.14 
(specie)  per  million  United  States  gallons. 

For  a  delivery  of  12,000,000  United  States  gallons  daily,  this  would  make 


16  REPORT    ON    THE 

the   cost  of  attendance,  repairs,   and   maintenance,   equal   to  $4,997   (specie) 
per  annum. 

Mr.  Hack,  the  Engineer  of  the  West  Middlesex  Water  Works,  London, 
stated  the  cost  of  filtering  as  about  10  shillings,  ($2.40  specie)  per  million  impe- 
rial gallons.  These  works  are  very  economically  managed,  and  this  amount 
includes  the  capital  invested.  On  the  supposition,  as  before,  that  each  tenement 
used  300  imperial  gallons  per  diem,  or  109,500  per  annum,  equal  to  131,435 
United  States  gallons,  the  cost  per  tenement  is  in  this  case  but  13  pence,  equal 
to  26  cents  (specie). 

The  first  cost  of  such  works  varies  with  the  nature  of  the  ground,  the  cost  of 
material  at  the  particular  place,  and  the  character  of  the  construction.  We  can- 
not therefore  infer  from  any  one  place,  except  in  very  general  terms,  the  expend- 
itures to  be  encountered  at  another  for  the  same  extent  of  water  supply. 

I  have  already  said  that  the  use  of  settling  basins  forms  a  necessary  and  an 
economical  preliminary  to  the  use  of  the  filter  bed  in  all  cases,  and  especially 
during  those  months  of  the  year  when  the  water  is  very  turbid. 

In  a  temperate  climate,  such  as  England,  it  is  of  little  consequence  how 
large  these  settling  basins  are  made,  provided  that  the  depth  of  water  is  not 
less  than  8  or  10  feet,  and  that  it  is  not  held  unchanged  for  any  great  length  of 
time. 

But  in  our  warm  climate  it  will  be  advantageous  to  have  the  settling  basins 
as  small  as  practicable  consistent  with  the  due  preparation  of  the  water  for  the 
filters. 

This  preparation,  our  experiments  upon  the  Mississippi  water  have  shown, 
can  be  secured  in  24  hours,  Within  that  time,  in  still  water,  the  heavier  portion 
of  the  sediment  in  suspension  sinks  to  the  bottom,  leaving  the  water  thoroughly 
discolored  still,  but  holding,  as  respects  weight,  a  very  small  part  of  the  original 
matter.  This  part,  which  even  in  still  water  settles  and  disappears  very  slowly, 
is  intercepted  and  separated  readily  and  speedily  by  the  sand  filter,  leaving  the 
water  invariably  clear  and  limpid. 

Under  this  arrangement  we  have  the  water  but  24  hours  still ;  during  the  rest 
of  the  time  it  is  in  motion. 

To  make  the  arrangement  efficient  under  all  circumstances  there  should  be 
four  settling  basins,  each  of  capacity  to  hold  12  millions  of  gallons  with  not  less 
than  12  feet  in  depth  of  water  when  full.  When  a  greater  capacity  is  required 
the  walls  could  be  carried  up,  and  a  greater  depth  of  water  Obtained. 

With  the  four  basins,  there  would  be  one  filling,  one  in  which  the  water  was 
still  undergoing  settlement,  one  in  which  the  water  was  being  drawn  off',  and 
one  upon  which  the  process  of  removing  the  stuff  deposited  on  the  bottom  could 
be  going  on  without  interrupting  the  duty  required  of  the  others. 

Waste  pipes  from  each  settling  basin  to  the  river  would  enable  the  attend- 


FILTRATION   OP   RIVER    WATERS.  17 

r 

ants  to  scour  or  flush  off  at  intervals  the  lowest  three  feet  of  the  water,  and  by 
some  manipulation  to  pass  off  with  it  more  or  less  of  the  accumulated  sediment. 
It  never  was  supposed  that  this  deposit  would  flow  off  without  this  kind  of  assist- 
ance, and  it  can  only  be  determined  by  experience  whether  it  will  be  cheaper  to 
run  it  out  by  wheelbarrows  or  to  carry  it  off  by  mixing  it  with  water. 

If  it  should  be  desired  to  use  settling  basins  without  filters,  they  ought  to 
be  much  larger  than  indicated  above  to  secure  approximately  the  same  results. 
They  would  not  be  so  economical  in  first  cost  if  of  sufficient  size,  but 
they  might  be  more  economical  in  attendance  ;  but  it  is  to  be  remembered 
that  in  this  connection,  having  in  view  their  probable  dimensions,  they  would  be 
an  experiment  which  it  might  be  interesting  to  have  made,  but  which  could  not 
be  advised,  that  I  know  of,  on  the  faith  of  its  having  succeeded  elsewhere.  Even 
where  very  large  gathering  reservoirs  have  been  available,  as  at  Liverpool  and  at 
Dublin,  filter  beds  have  been  constructed  on  the  usual  scale,  to  get  rid  of  that  slight 
discoloration  which  frequently  remains  in  large  bodies  of  water,  and  to  meet  the 
turbid  character  of  such  water  when  the  reservoir  is  low,  as  well  as  to  intercept 
the  organic  impurities  referred  to  elsewhere. 

It  remains  to  speak  of  the  natural  filter,  of  which  we  have  specimens  at 
Genoa,  Toulouse,  Lyons,  Angers,  and  Perth. 

The  descriptions  of  the  works  at  these  places  will  show  that  this  mode  of 
obtaining  a  supply  of  clear  water  has  been  eminently  successful,  as  regards  the 
quality,  if  not  always  as  regards  the  quantity.  The  character  of  the  water  at  the 
places  referred  to  is  indeed  unobjectionable,  the  slight  increase  of  hardness  at  Lyons 
as  compared  with  the  Rhone  water  being  too  small  to  be  of  any  moment.  The 
water,  indeed,  in  this  case,  is  not  made  clear  and  pure  by  any  artificial  process  ; 
it  is  received  from  the  underground  flow  as  from  springs,  and  has  not  been 
exposed  to  light  or  to  surface  contamination  of  any  kind. 

Bordering  upon  all  rivers  there  are  found  at  intervals  narrow  plains  of 
gravel  or  sand  brought  down  and  deposited  there  by  the  river  under  the  varying 
positions  of  its  channel  way.  When  these  beds  of  gravel  extend  to  a  dep'th 
below  the  bottom  of  the  neighboring  stream,  they  will  always  be  found  saturated 
with  water  mainly  derived  from  that  stream,  and  however  turbid  the  water  of  the 
river,  this  underground  flow  will  always  be  found  clear,  provided  that  we  tap  it 
at  a  reasonable  distance  from  the  channel  way.  The  cities  referred  to  derive 
their  supplies  of  water  from  gravel  accumulation  of  this  kind — Genoa  at  a 
considerable  distance  from  the  city,  but  the  other  places  in  the  immediate  vicinity 
of  the  several  cities. 

Covered  galleries  have  been  carried  through  these  beds  of  gravel  at  depths 
sufficiently  below  the  channel  of  the  neighboring  stream  to  insure  a  supply  of 
water  within  the  gallery  during  the  lowest  stages  of  its  water.  The  water  in 
these  gravel  beds  rises  and  falls  with  the  height  of  the  water  in  the  river,  and 


18  REPORT    ON    THE 

unless  the  galleries  were  placed  below  its  lowest  water  they  would  obviously 
become  dry  and  would  cease  to  deliver  at  its  lowest  stage.  These  galleries  are 
of  various  sizes  and  of  various  widths,  eight  to  thirty  feet  in  width  being  the 
latest  practice.  But  the  experience  of  one  place  will  seldom  be  applicable  to 
another.  The  character  of  the  neighboring  stream  and  the  fineness  or  coarse- 
ness of  the  gravel  or  sand  in  which  the  galleries  are  placed,  influence  impor- 
tantly the  rate  of  supply. 

As  regards  St.  Louis,  although  I  have  already  in  a  former  report, 
expressed  an  unfavorable  opinion  in  regard  to  the  applicability  of  this  method 
here,  it  seems  to  me  important  that  an  experiment  should  be  made  upon 
the  river  plain  above  Bissell's  Point,  to  ascertain  whether  the  material  of  that 
bottom  is  sufficiently  open  and  gravelly  to  secure  a  supply  of  water  in  this  way, 
what  length  of  gallery  would  probably  be  necessary  there,  and  whether  the 
water  would  be  of  the  same  character  as  the  Mississippi  water.* 

If  clear  water  could  be  obtained  there  by  underground  galleries  at  a  rea- 
sonable cost,  it  would  be  more  satisfactory  to  the  inhabitants  probably,  than  if 
the  river  water  were  rendered  equally  pure  to  them  by  filtering  or  settling 
reservoirs  operating  above  ground.  The  experiment  should  be  on  a  sufficiently 
large  scale  to  give  some  confidence  as  to  the  ultimate  results. 

Although  the  filtering  galleries  of  the  Genoa  Water  Works  give  larger 
results  than  any  others  that  I  am  acquainted  with,  no  conclusion  can  be  drawn 
from  them  which  would  be  applicable  to  our  case,  the  circumstances  being  so 
very  different. 

At  Toulouse,  Lyons,  Angers,  and  Perth,  the  circumstances  bear  a  closer 
resemblance  to  our  own,  though  I  fear  that  the  materials  of  the  plain  above 
Bissell's  Point  may  prove  finer  and  closer  than  the  sand  and  gravel  deposits  of 
the  places  above  mentioned. 

These  galleries  are  all  of  stone  masonry,  open  at  bottom..  The  water 
in  all  these  cases  enters  principally  from  the  bottom,  and  the  estimated 
rate  of  delivery  in  these  galleries  is  generally  referred  to  the  area  of  the 
bottom.  • 

The  flow  into  them  must  be  at  a  velocity  which  shall  not  carry  sand  or 
any  kind  of  material  with  the  water.  There  is,  therefore,  no  danger  of  under- 
mining the  side  walls. 

The  first  galleries  built  at  Toulouse  and  Lyons  were  two  small  in  size  to 
give  the  best  results  there.  The  latest  galleries  have  been  made  larger.  At 
Toulouse  Ik  feet  wide,  at  Lyons  33  feet  wide.  The  galleries  at  Angers  and 
Perth  are  too  small  for  your  purpose. 


*  This  recommendation  was  not  carrried  into  effect,  the  Commissioners  not  feeling  warranted,  from  such 
information  as  they  could  obtain,  in  risking  the  delay  which  a  sufficient  experiment  would  necessarily  entail. 


FILTRATION    OF   RIVER    WATERS.  19 

The  minimum  deliveries   of  these  underground  galleries  per   diem   per 
square  foot  of  their  bottom  areas  is  as  follows  : 


CUBIC  FEET. 

U.  S.  GALLONS. 

Toulouse,  the  new  gallery  

38.50 

288 

19.64 

147 

Angers,  the  latest  gallery  

40.10 

300 

Perth  

24.32 

182 

The  lower  the  gallery  can  be  carried  below  the  lowest  stage  of  the  river 
the  more  safe  and  abundant  it  is  said  will  be  the  supply. 

If  we  suppose  the  galleries  to  be  20  feet  in  width,  and  that  a  rate  of  200 
United  States  gallons  per  square  foot  of  bottom  could  be  obtained  from  them 
at  low  water  of  the  Mississippi,  the  length  of  gallery  required  to  give  1,000,000 
gallons  daily  would  be  250  feet,  and  for  a  supply  of  12,000,000  it  would  require 
a  length  of  3,000  feet. 

In  other  words,  the  bottom  area,  to  produce  this  last  quantity,  would  be 
60,000  square  feet.  The  filtering  galleries  and  basins  at  Lyons  have  an  aggre- 
gate of  57,706  square  feet,  giving,  at  low  water  of  the  Rhone,  a  daily  delivery 
of  about  six  millions  U.  S.  gallons,  but  the  galleries  of  the  other  cities  give 
much  higher  results,  as  you  have  seen,  than  the  Lyons  galleries. 

The  river  water  which  finds  its  way  into  the  deposit  of  sand  or  gravel 
where  the  galleries  are  placed,  must  have  deposited  somewhere  the  sediment 
held  by  it  in  suspension  while  in  the  river  channel.  I  could  not  learn,  however, 
that  the  filtering  galleries  became  unserviceable  from  any  such  cause.  The 
deposit  which  takes  place  upon  the  river  bottom  in  the  ordinary  and  in  the  low 
stage  of  its  water  is  removed,  it  is  asserted,  in  time  of  floods,  when  the  bottom 
is  scoured  of  all  its  light  matter,  and  the  coarser  earths  composing  -it  become 
in  this  way  periodically  exposed.  This,  and  the  fact  that  the  water  drawn  from 
a  gravel  bed  of  this  description  percolates  into  it  from  a  very  extended  face  as 
compared  with  any  artificial  filter,  may  account  for  the  continued  regularity  of 
flow  into  the  natural  filtering  galleries. 

In  the  accompanying  descriptions  there  will  be  found  some  other  modes 
of  filtering  in  practical  use,  but  I  refrain  from  alluding  to  them  here,  as  they 
are  not  applicable  to  your  case,  nor  can  they  be  recomnlended  for  similar  works. 
The  two  modes  of  sand  and  gravel  filtration  to  which  your  attention  has  been 
specially  directed — the  natural  filter  and  the  artificial  sand  filter — have  each  of 
them  met  the  test  of  long  and  successful  use  ;  and  when  the  natural  filter  is 
not  available,  the  artificial  filter  may  always  be  safely  depended  on  in  connec- 


20  REPORT    ON    THE 

tion  with  subsiding  reservoirs  as  competent  to  render  any  river  water,  however 
turbid,  entirely  limpid  and  satisfactory  in  that  respect  for  domestic  use. 
Respectfully  submitted  by 

JAMES  P.  KIRKWOOD. 


NOTE. — April,  1869. — New  works  for  the  supply  of  the  city  of  St.  Louis  with  water  are  now  in  the  course  of 
construction  under  the  charge  of  Mr.  Thomas  J.  Whitman  as  chief  engineer,  the  undersigned  being  connected 
with  them  only  as  consulting  engineer.  These  works  include  settling  reservoirs,  but  the  public  mind  of  St. 
Louis,  so  far  as  it  has  been  expressed,  does  not  yet  seem  to  consider  filtration  important 

I  will  take  advantage  of  this  note  to  mention  the  works  now  under  construction  (May,  18G9),  for  supplying 
the  city  of  Newark  with  water,  as  presenting  the  only  instance  in  the  United  States  that  I  know  of  where  provision 
is  made  for  the  filtration  of  the  river  water  from  which  the  supply  is  derived.  In  this  case  two  basins,  350  feet 
by  150  feet  each,  have  been  constructed  alongside  of  the  Passaic  river,  above  the  village  of  Belleville.  They  have 
eight  feet  depth  of  water  in  them  now.  The  flat  or  bottom  land  on  which  the  basins  are  placed  is  understood  to 
consist  of  sand  and  gravel,  resting  on  a  sandstone  rock.  The  river  is  distant  about  200  feet  from  the  basins.  The 
water  which  fills  them  is  evidently  dependent  mainly  on  the  river  as  its  source  of  supply,  not  drawn  exclusively 
from  that  part  of  the  river  immediately  bordering  the  basins,  but  as  well  from  the  plain  above  and  below,  which 
mast  be  saturated  with  the  same  water.  These  basins  collect  the  water  on  the  same  principle  as  the  filtering 
galleries  at  Lyons  and  Toulouse.  They  are,  however,  open  basins,  while  the  French  filtering  galleries  are  all 
covered.  The  basins  are  bordered  by  vertical  stone  walls  of  excellent  masonry,  very  neat  and  substantial  in 
character.  Mr.  Bailey  is  the  engineer  of  the  works. 

At  the  Hamilton  Water  Works,  in  Canada,  built  after  the  designs  of  Mr.  Keefer,  another  instance  occurs  of 
this  kind  of  surface  filtration.  The  water  there  is  not  drawn  directly  from  the  hike,  but  from  an  artificial  pond 
bordering  the  lake.  The  lake  water  finds  its  way  into  this  pond  through  the  intervening  beach  of  gravel  which 
acts  as  a  filtering  medium.  The  pond,  however,  is  not  so  elaborately  finished  as  the  Newark  basins. 

J.  P.  K. 


FILTKATION    OF   KIVBU    WATERS.  21 


DESCRIPTIONS  OF  THE  FILTERING  WORKS  REFERRED  TO 

IN  THE  REPORT. 


LONDON,  June,  1866. 

The  metropolis  of  London  derives  its  supply  of  water  at  present  from  the 
Thames,  the  river  Lea  with  certain  springs  in  the  valley  of  the  Lea,  and  from  a 
series  of  chalk  wells  in  the  valley  of  the  Ravensbourne,  sunk  on  the  upper  side 
of  a  fault  which  occurs  in  the  chalk  basin  there,  in  the  neighborhood  of  Deptford. 

The  proportions  are  nearly  as  follows  : 

From  the  Thames 49  parts  of  the  whole. 

From  the  Lea 44     " 

From    Chalk  Wells  in    the  Ravensbourne 

Valley 7     " 

100 

The  present  condition  of  the  supply  is  in  a  measure  due  to  the  legislation 
which  followed  the  visitation  of  the  cholera  in  1849,  and  the  result  when  com- 
pared with  what  was  tolerated  before  that  time  must  be  admitted  to  be  very 
satisfactory. 

The  past  history  of  the  waters  delivered  to,  and  submissively  endured  by, 
the  populations  of  London  and  Paris,  may  be  studied  as  instances  of  how  much 
discomfort  and  filth  in  this  direction  communities  will  suffer  before  being  roused 
to  insist  upon  the  remedial  measures  within  their  reach. 

Previous  to  1852,  when  the  Parliamentary  investigations  following  1849 
ended  in  a  bill  to  provide  for  and  insure  the  improvement  of  the  water  supplied 
to  the  city,  the  Thames  Companies  drew  their  supplies  from  the  river  within  the 
city  lines,  where  the  water,  besides  being  turbid  more  or  less  at  all  times,  was 
contaminated  by  the  sewerage  of  the  largest  city  population  in  Europe. 

After  1852  the  Thames  Companies  were  required  to  get  their  water  from  a 
point  on  the  Thames  above  the  city  influences  and  above  the  tidal  flow  ;  they 
were  also  all  required  to  filter  the  water  intended  for  domestic  use,  including  in 
this  term  all  water  except  that  used  for  street  or  fire  purposes  ;  but  as  th<?  latter; 
when  delivered  separately,  involves  a  separate  pipe  distribution,  the  filtered 
water  is,  with  most  of  the  companies,  applied  to  the  entire  service  of  the  district. 


22  LONDON. 

Although  my  visit  to  the  London  works  had  reference  simply  to  the  modes 
of  nitration  in  use  there,  and  any  details  outside  of  that  subject  might  seem  to 
be  in  this  connection  superfluous,  I  have  thought  that  a  general  knowledge  of 
the  schemes  of  supply  would  be  interesting,  and  in  some  measure  necessary  to  a 
proper  appreciation  of  the  filtering  arrangements. 

The  population  of  the  metropolis  was  estimated  in  1849  at  2,000,000  ;  in 
1861  the  census  gave  2,803,034  ;  in  1865  it  was  estimated  by  Mr.  Bateman  at 
3,000,000  ;  in  June,  1866,  the  Registrar-General  gave  it  as  3,067,538  ;  at  this 
date,  June,  1866,  it  is  generally  supposed  to  exceed  somewhat  three  millions  of 
souls,  say,  3,060,000. 

The  waters  delivered  to  the  metropolis  are  supplied  by  eight  different  com- 
panies to  as  many  separate  districts. 

The  following  table  is  in  large  part  prepared  from  a  return  made  in  1866. 
It  shows  the  reported  deliveries  of  water  then  by  each  company,  to  which  I  have 
added  the  aggregate  areas  of  the  filtering  basins  provided  at  the  different  works 
and  some  other  statistics  : — 


LONDON. 


23 


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From  Springs  in  the  chalk,  1866,  ir 

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Hardness  after  boiling,  by  Dr.  Let 
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Hardness  as  given  by  Dr.  Frankla 

In  each  case  1  degree  =  1  part  c 
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Aggregate  areas  of  the  filter  basins 

Aggregate  areas  of  settling  basins. 

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Number  of  houses,  1866,  excluding 
premises  and  public  buildings.  . 

Bate  per  house  per  diem  

Daily  average  per  year,  1868  

24  LONDON. 

If  we  take  the  given  population  supplied  at  three  millions,  and  the  aver- 
age daily  delivery  at  ninety-seven  million  gallons,  we  have  a  rate  of  daily  con- 
sumption per  head  of  32s  imperial  gallons,  this  amount  being  inclusive  of  all 
water  used  for  manufactories,  shipping,  fires,  streets,  and  other  purposes. 

The  Thames,  at  an  unusually  low  stage  of  the  river,  in  August,  1868,  as 
measured  by  Mr.  Hamilton  N.  Fulton,  near  Tottenham  Lock,  was  delivering 
256,000,000  gallons  in  24  hours.  In  1867,  its  lowest  state  was  mentioned  by 
Mr.  Simpson  as  being  at  no  time  less  than  300,000,000  gallons  per  diem.  The 
water  companies,  it  will  be  seen  farther  on,  withdrew  a  little  over  one-fifth  of 
the  lowest  of  1858,  or  57,900,000  imperial  gallons. 

The  drainage  area  of  the  Thames  above  Hampton  is  stated  to  include 
2,352,640  acres,  or  3,676  square  miles. 

The  drainage  area  of  the  river  Lea  at  Fields  Weir,  near  to  where  it  is  tapped 
by  the  New  River  Company,  is  stated  to  measure  444  square  miles,  and  the  en- 
tire drainage  of  the  river  at  the  point  above  Lea  Bridge  where  the  river  is 
tapped  by  the  East  London  Water  Works  Company,  I  estimate  as  equal  to  640 
square  miles.  I  find  it  difficult  to  get  at  the  minimum  flow  of  this  river,  but 
it  seems  plain  that  it  has  more  than  once  fallen  below  the  amount  which  the 
two  water  companies  are  entitled  to  draw  from  it,  making  a  recourse  to  storage 
reservoirs  therefore  indispensable. 

I  visited  the  works  of  all  the  Metropolitan  Water  Companies,  and,  although 
my  object  was  to  obtain  the  required  information  in  regard  to  their  filtering 
processes  especially,  I  was  permitted  at  the  same  time  to  take  notes  of  the 
general  dimensions  of  their  pumping  engines.  The  information  thus  collected, 
however,  is  necessarily  incomplete.  Neither  the  time  at  my  own  disposal  nor 
the  time  of  the  officials,  to  say  no  more,  permitted  me  to  acquire  that  fulness 
of  detail  that  was  desirable.  Such  as  it  is,  however,  it  may  prove  to  others,  as 
it  has  done  to  myself,  useful  as  a  basis  of  reference.* 

All  of  the  water  delivered  to  London  undergoes  a  process  of  filtration 
through  beds  of  sand  and  gravel,  with  the  exception  of  a  portion  of  the  water 
used  for  fire  purposes  and  for  street  washing,  and  with  the  exception  of  the 
water  delivered  by  the  Kent  Water  Company. 

This  last  water  is  obtained  from  wells  sunk  in  the  chalk,  and  does  not  re- 
quire filtration. 

Allowing  for  these  deductions,  the  amount  of  water  filtered  daily  must 
reach  about  eighty  million  gallons.  The  aggregate  area  of  the  filter  beds  at  the 
works  of  the  seven  companies  herein  described  amounts  to  2,239,010  square 
feet,  or  51.10  acres.  If  we  take  six-sevenths  (f)  of  this  area  as  in  daily  use, 
the  other  seventh  being  under  repair,  it  would  give,  as  compared  with  the 
eighty  million  gallons  filtered,  an  average  rate  of  41 2  imperial  gallons  per 

*  See  Appendix. 


UNIVERSITY  OF 

OF  CIVIL.  ENGINEERING 
BERKELEY.  CALIFORNIA 

LONDON.  25 

square  foot  of  sand  area  per  diem  ;  but  at  least  three-fourths  of  the  London 
supply  is  delivered  during  the  day  hours  (6  A.  M.  to  6  P.  M.),  and  for  a  certain 
portion  of  the  mid-day  hours  in  summer,  the  consumption  may  be  taken  at 
double  the  average  which  refers  to  the  diem  of  24  hours.  The  rate  of  filtration, 
therefore,  during  the  day  may  at  times  reach  an  average  rate  of  83  gallons  per 
square  foot — a  rate  which  exceeds  by  11  gallons  the  average  (72)  which  the 
best  authorities  recommend  as  the  proper  limit. 

All  the  companies  deriving  their  supplies  from  the  Thames  are  required  by 
law  to  take  the  water  from  the  river  above  Teddington  Lock  ;  in  other  words, 
above  tidal  influence,  and  above  the  influence  of  the  sewerage  of  London,  Ted- 
dington Lock  being  the  first  lock  on  the  river  above  its  tidal  flow.  The  law  also 
requires  that  all  storage  reservoirs  for  filtered  water  situated  within  five  miles 
of  the  centre  of  London  (St.  Paul's),  shall  be  covered.  All  of  them  are, 
therefore,  arched  over.  The  storage  reservoirs,  probably  on  account  of  the 
great  expense  attending  their  construction  and  the  cost  of  property  within  the 
city,  are  most  of  them  comparatively  small,  and,  while  they  assist  to  meet  any 
extraordinary  increase  of  consumption,  as  in  the  case  of  fires  to  which  the 
pumping  engines  of  the  night  service  might  not  be  able  to  respond  at  once, 
they  are  rarely  sufficient  to  enable  the  entire  engine  power  of  any  company  to 
be  at  rest  during  the  night  hours,  far  less  to  admit  of  one  or  more  days'  inter- 
mission of  the  pumping  operations  to  meet  any  extraordinary  emergency.* 

August,  1868. — Since  the  above  introductory  remarks  were  written  and  this 
report  presented  to  the  Board,  a  short  visit  to  England,  in  July,  1868,  has  per- 
mitted me  to  visit  again  most  of  the  pumping  stations  of  the  different  London 
water  companies. 

Since  my  former  visit  in  1866,  the  Chelsea  Company  has  added  a  new  set- 
tling reservoir  at  Thames  Ditton,  and  is  now  constructing  two  additional  filter 
beds  there;  the  Lambeth  Company  has  more  than  doubled  its  filtering  area, 
and  has  provided  for  three  settling  reservoirs  in  connection  with  these,  one  of 
which  is  finished  and  the  other  two  under  construction. 

The  Grand  Junction  Company  is  constructing  three  new  filter  beds  and  an 
additional  settling  reservoir  at  Hampton,  aad  has  also  under  construction  an 
additional  storage  reservoir  at  Camden  Hill  ;  and  the  New  River  Company  has 
constructed  two  new  filter  beds  at  Stoke  Newington.  I  crave  leave,  therefore, 

*  The  Metropolitan  water  acts  prescribe  as  follows  : 

From  and  after  31st  August,  18G5,  no  company  to  take  any  water  from  the  Thames  below  Teddington  Lock, 
except  the  Chelsea  Company. 

From  and  after  the  31st  August,  1856,  no  water  to  be  taken  by  the  Chelsea  Company  below  Teddington  Lock. 

From  and  after  31st  August,  1855,  every  reservoir  within  a  distance  in  a  straight  line  of  five  miles  from  St. 
Paul's  Cathedral  shall  be  roofed  or  otherwise  covered  over,  except  storage  reservoirs  for  collecting  the  water  before 
nitration,  and  except  reservoirs  for  water  used  for  street  cleaning  or  fires,  and  not  for  domestic  use. 

From  and  after  the  31st  December,  1855,  every  company  shall  effectually  filter  all  the  water  supplied  by  them 
within  the  metropolis  for  domestic  use,  excepting  any  water  which  may  be  pumped  from  wells  into  a  covered  re- 
servoir or  aqueduct  without  exposure  to  the  atmosphere. 


26  LONDON. 

to  revise  that  part  of  my  report  which  referred  to  the  London  Works  so  as  to 
meet  more  nearly  the  present  condition  of  things  there,  and  with  the  permission 
of  the  Board  of  Water  Commissioners,  the  changes  and  improvements  referred 
to  are  now  incorporated  accordingly. 

To  appreciate  the  present  situation  of  the  London  water  supply  in  a  sani- 
tary point  of  view,  the  report  of  Dr.  Parr  on  the  cholera  epidemic  of  1866 
should  be  read.  The  sewerage  of  the  many  villages  within  the  valleys  of  the 
Thames  and  the  Lea  finds  its  way  into  these  streams  now.  When  the  rivers 
are  as  low  as  they  have  been  this  season,  this  cannot  but  affect  the  purity  of  the 
water,  which,  while  it  can  be  clarified  and  made  perfectly  limpid  by  sand  filtra- 
tion, cannot  by  that  process  be  dispossessed  of  any  noxious  gases  which  it  may 
have  from  such  sources  absorbed,  nor  of  some  of  the  very  minute  organisms 
due  to  such  causes.  A  law  passed  recently  for  the  defence  of  river  waters 
against  such  sources  of  contamination,  will,  to  some  extent,  it  is  hoped,  correct 
the  evil  referred  to,  though  it  cannot  entirely  remove  it. 

In  this  place  it  may  be  well  to  keep  in  mind  that  the  water  which  will 
satisfy  a  chemist  will  not  always  be  a  safe  water  for  public  use.  Chemistry  can- 
not always  detect  the  nicer  shades  of  impurity  which  should  render  a  water 
objectionable  to  the  consumer.  Impurities  which  the  sense  of  smell  or  of  taste 
can  detect,  the  researches  of  chemistry  fail  to  expose,  and  for  that  reason  are 
apt  to  ignore. 

Dr.  Letheby,  the  Professor  of  Chemistry  in  the  London  Hospital,  and  Medical 
Officer  of  the  city,  has  acknowledged  "  that  we  have  not  at  the  present  time  any 
absolute  test  for  discovering  organic  matters  in  water,  much  less  the  nature  of 
those  organic  matters."  "  We  cannot  distinguish  absolutely  vegetable  from  ani- 
mal substances  in  water  unless  they  are  in  so  large  a  quantity  as  to  be  able  to 
show  us  their  marked  properties,  when  they  can  be  tested  ;  but  under  common 
every-day  circumstances  of  organic  matter  in  water,  we  cannot  say  whether  it 
is  vegetable  or  animal  organic  matter."  The  General  Board  of  Health  in  their 
.report  of  1850,  speaking  of  the  Thames  river,  makes  the  following  remarks  to 
the  same  effect :  "  High  up  the  river  the  water  is  so  transparent  that  the 
bottom  is  visible  more  than  eight  feet  deep.  As  the  examiner  proceeds  down- 
wards the  transparency  diminishes,  and  the  water  becomes  turbid  until  it 
reaches  the  metropolis,  where  nothing  is  to  be  seen  within  a  few  inches  beneath 
the  surface.  It  was  the  task  of  Dr.  Angus  Smith  to  follow  the  river  and  ascer- 
tain by  analysis  more  closely  than  had  hitherto  been  done,  the  nature  and 
quantities  of  these  variable  additions.  This  he  has  done  carefully  with  all  the 
aid  which  chemistry  is  capable  of  affording.  But  as  yet  chemistry  has  failed  to 
determine  the  qualities  of  much  animal  and  vegetable,  and  above  all,  gaseous 
matter,  that  is  perceptible  and  offensive  both  to  the  taste  and  to  the  smell." 

The  works  will  now  be  described  as  shortly  as  practicable,  in  the  order  in 
which  they  were  visited. 


THE  CHELSEA  WATER  WORKS.  27 


THE    CHELSEA    WATER    WORKS 


The  water  supplied  by  this  company  is  derived  from  the  river  Thames. 
The  filtering  works  are  situated  on  the  right  bank  of  the  Thames,  close  to  the 
river  at  Seething  Wells,  near  Thames  Ditton. 

The  original  works  of  the  company  were  situated  at  Chelsea  ;  they  were 
removed  in  1852,  to  Seething  Wells. 

The  accompanying  sketch  will  explain  the  form  of  these  works  (Plate  4). 

The  narrowness  of  the  strip  of  ground  available,  controlled  the  arrangement 
here,  and  has  obliged  the  engineer  to  place  the  engine-houses  rather  inconve- 
niently away  from  the  filter  beds.  There  are  three  settling  reservoirs  and  two 
filter  beds.  The  settling  reservoirs  have  each  a  water  area  of  about  one  and  a 
half  acres.  The  filter  beds  have  each  a  sand  area  of  about  one  acre  or  very 
nearly  44,000  superficial  feet.  Two  new  filter  beds  were  being  constructed 
during  the  summer  of  1868,  of  the  same  capacities  very  nearly  with  those  now 
in  use. 

The  settling  basins  have  a  depth  of  water  in  them  of  six  to  ten  feet,  vary- 
ing with  the  water  in  the  Thames.  The  first  and  second  from  the  filters,  are 
each  272  feet  long  by  226  feet  wide  at  the  top  of  the  banks,  with  inside 
slopes  of  1  to  1. 

The  third  has  about  the  same  water  area,  but  is  a  little  differently  shaped, 
to  meet  the  situation  of  the  ground.  The  water  passes  into  each  freely  from  the 
Thames  through  a  sluice-way,  and  stands  at  the  same  level  as  the  river  water. 

In  the  sluice-way  there  are  screens.  At  the  side  of  each  reservoir  oppo- 
site to  the  sluice-way,  the  water  passes  to  the  filter  beds  by  means  of  a  24-inch 
pipe  controlled  by  a  stopcock.  A  rough  semicircular  filter  of  gravel  and  small 
stones,  shown  on  the  sketch,  intervenes  between  the  pipe  mouth  and  the  water 
of  the  basin,  and  intercepts  any  floating  grasses  or  other  impurities  that  may 
have  passed  the  screens. 

The  condition  of  things  here  does  not  admit  of  the  water  remaining  at 
absolute  rest  in  either  basin.  It  enters  at  one  side  in  each  case  and  passes 
slowly  through  to  the  other  side,  the  movement  being  more  rapid  during  the 
day  than  during  the  night. 


28  THE  CHELSEA  WATER  WORKS. 

This  slow  passage  admits  of  a  sufficient  amount  of  deposition  in  the  pres- 
ent state  of  the  Thames  (June,  1866),  when  its  water  is  but  very  slightly  turbid ; 
but  when  the  river  is  in  flood  and  carrying  much  sediment,  the  preparation  here 
for  the  filter  bed  must  be  insufficient. 

The  settling  basins  are  said  to  be  cleaned  out  twice  a  year.  To  effect  this 
the  water  is  drawn  off  through  an  18-inch  pipe  into  a  silt  well,  whence  it  is 
pumped  off  by  two  small  pumping  engines  appropriated  to  this  service,  the  mud 
at  the  bottom  of  the  settling  basin  being  stirred  up  during  the  process  of  pumping, 
so  that  the  greater  part  of  it  flows  with  the  water  into  the  drain-well  of  the 
pump.  The  dirty  water  and  slush  pass  into  a  sewer  which  has  its  outlet  on  the 
Thames,  about  half  a  mile  below  the  works. 

The  pipe  (24-inch)  which  takes  the  water  from  the  settling  basins  to  the 
filter  beds,  passes  round  to  the  extreme  side  of  the  beds,  and  delivers  the  water 
upon  each  bed  by  6  branch  pipes,  of  6  inches  diameter  each. 

After  a  filter  bed  has  been  cleaned,  and  while  its  surface  of  sand  is  bare, 
the  covering  it  again  with  water  is  an  operation  requiring  considerable  circum- 
spection. The  sand  will  be  rutted  into  channels  if  the  water  is  let  on  rapidly, 
or  blown,  if  the  process  is  not  effected  so  slowly  as  to  admit  of  the  escape  of 
what  air  may  be  lodged  within  the  filter  bed. 

After  the  filter  is  well  covered  and  in  use,  the  water  may  be  delivered  upon 
it  as  rapidly  as  it  can  use  it. 

The  branch  pipes  above  mentioned  do  not  deliver  the  water  directly  upon 
the  sand  surface,  but  they  deliver  it  into  wooden  troughs  10  feet  long,  12  inches 
wide  inside,  and  twelve  inches  deep.  From  these  troughs,  which  are  imbedded 
in  the  sand,  the  water  flows  over  their  edges  upon  the  filter  beds  without  dis- 
turbing the  sand. 

When  a  filter  bed  is  bare  here,  it  is  filled  from  the  surface,  and  the  attendant 
says  that  he  finds  no  difficulty  in  effecting  this  and  getting  rid  of  the  air,  except 
that  the  operation  must  be  begun  slowly. 

There  are  air  pipes  along  the  two  ends  of  each  filter  bed,  connected  with  the 
clear  water  drains,  but  these  air  pipes  can  be  of  little  service,  except  when  the 
water  is  entirely  drawn  off  from  the  filtering  materials,  which  seems  rarely  to  be 
the  case.  Usually  the  water  when  drawn  off  is  not  lowered  more  than  two  feet 
below  the  surface  of  the  sand. 

I  saw  one  of  the  filters  bare  in  February,  1866.  At  the  time  of  my  last 
visit  they  were  both  covered.  The  depth  of  water  in  each  was  82  feet. 

The  water  delivered  into  London  from  these  works  in  June,  1868,  was 
reported  to  average  daily  9,333,900  imperial  gallons,  and  in  July,  1868, 
9,748,100  imperial  gallons. 

Assuming  550,000  gallons  to  consist  of  the  unfilterod  water  delivered  for  street 
and  fire  purposes,  there  remains  say  9,200,000  of  filtered  water  delivered  per 


THE  CHELSEA  WATER  WORKS.  29 

diem  in  July.  Had  this  been  an  ordinary  year  as  regards  temperature,  the 
delivery  of  filtered  water  would  not  probably  have  exceeded  a  per  diem  of 
8,000,000. 

This  Company,  as  well  as  each  of  the  other  four  Thames  Water  Companies, 
has  a  right  to  take  from  the  river  twenty  millions  imperial  gallons  per  diem. 
At  this  date  the  five  companies  take  a  little  exceeding  fifty  million  gallons  daily 
from  the  stream. 

To  avoid  to  some  extent  the  excess  of  duty  thrown  upon  one  of  these  filter 
beds  by  the  disuse  of  the  other  (during  the  process  of  cleansing),  a  low  earthen 
bank  has  been  run  across  each  of  the  filters,  dividing  each  into  two,  and  making 
practically  four  filter  beds.  This  earthen  division  being  but  a  make -shift  of  not 
more  than  2 2  feet  in  height,  the  water  is  partially  drawn  down  when  it  is 
brought  into  play.  The  effect,  however,  is  to  secure  the  use  approximately  of 
three-fourths  of  the  entire  filtering  surface,  leaving  but  one-fourth  necessarily  in 
disuse. 

The  two  filter  beds  have  a  joint  area  of  88,000  square  feet.  Assuming 
three-fourths  of  this  to  be  always  in  service,  there  are  60,000  square  feet  of  sand 
area  to  filter  ordinarily  80,000,000  gallons  of  water.  But  although  the  larger 
portion  of  this  amount  is  pumped  during  the  day  hours,  the  day  rate  of  filtration 
cannot  be  more  than  393,000  gallons  per  hour,  because  two  pairs  of  engines 
cannot  deliver  above  this  rate.  This  is  equal  to  6  gallons  per  square  foot  of 
filter  per  hour,  or  144  gallons  per  square  foot  per  diem  ;  with  the  whole  filtering 
area  in  use,  the  flow  is  reduced  to  107  gallons  per  square  foot  per  diem.  Both 
of  these  very  much  exceed  the  rate  which  the  Engineer  considers  best,  a  rate 
namely  of  about  72  gallons  per  square  foot  per  diem,  but  the  increase  of  the 
population  of  the  district  has  exceeded  the  anticipations  of  the  Company,  and  the 
filtering  works  have  fallen  behind  the  necessities  of  the  service. 

When  the  new  filter  beds  are  completed,  this  condition  of  things  will  be 
entirely  corrected. 

The  outer  walls  of  the  filter  beds  are  slope  walls  of  brick  on  edge  laid  at 
an  inclination  of  1  to  1. 

On  two  sides  of  each  filter  bed,  appearing  at  the  top  of  the  slope  walls,  are 
rows  of  3-inch  cast-iron  air  pipes,  communicating  with  the  drains  on  the  bot- 
tom of  the  filter  beds. 

The  pumping  power  at  work  during  the  day  is  about  double  of  what  is  at 
work  during  the  night. 

The  additional  charge  made  for  filtration,  Mr.  Simpson  stated  to  be  about 
four  shillings  and  sixpence  (one  dollar)  per  house  per  annum  on  the  average. 

The  materials  of  these  filters  consist  of  sand,  gravel,  shells,  and  small 
stones,  in  the  following  proportions  : 

4 


30  THE  CHELSEA  WATER  WORKS. 

Fine  sand 30  inches. 

Coarse  sand 6  inches. 

Shells 4  inches. 

Fine  gravel 6  inches. 

Large  gravel 24  inches. 

70  inches. 

Perforated  clay  pipes  are  imb  edded  in  the  large  gravel. 

The  thin  layer  of  shells  was  intended  to  intercept  any  sand  which  might 
follow  the  water. 

On  the  bottom  there  is  a  central  drain,  into  which  the  water  is  collected  by 
these  earthenware  perforated  pipes,  branching  from  it  across  the  bottom  on 
either  side.  These  drain  pipes  were  given  me  as  of  9,  8,  and  6  inches  in  diam- 
eter on  each  branch,  the  smallest  being  placed  furthest  from  the  central  drain. 
A  circular  well  of  about  12  feet  diameter  receives  the  filtered  water  ;  it  is  trans- 
mitted thence  by  a  cast-iron  pipe  to  the  pumping  engines,  which  are  situated  on 
the  opposite  side  of  the  Kingston  road,  as  shown  on  the  sketch.  At  the  time 
of  my  last  visit,  the  water  in  the  well  (at  noon)  stood  3  feet  below  the  water  on 
the  filter  beds,  both  of  which  were  then  in  full  use. 

The  water  in  the  well  varies  from  2  to  4  feet  below  the  level  of  the  water 
on  the  filters,  according  to  the  condition  of  the  beds. 

The  filter  beds  are  cleaned  off  from  once  in  six  to  once  in  twenty  days 
each,  according  to  the  condition  of  the  river.  The  amount  of  sand  taken  off 
does  not  exceed  half  an  inch,  and  this  is  washed  and  used  over  again.  A  cir- 
cular sieve  (kept  in  motion  by  one  of  the  small  engines)  into  which  the  water  is 
poured  from  perforated  iron  pipes,  is  used  for  cleansing  the  sand. 

The  position  of  the  engine-house  is  shown  on  the  sketch. 

There  are  six  double-cylinder  rotative  beam  engines  here,  working  in  pairs, 
having  one  fly-wheel  to  each  pair.  The  engines,  however,  can  be  uncoupled 
and  worked  separately.  Of  these  engines  the  first  and  second  pairs  are  known 
as  the  "A.  B."  and  "  C.  D."  engines  ;  the  third  pair,  furnished  in  1867,  as  the 
"  E.  F."  engines.  Each  pair  is  given  as  of  300-horse  power,  or  150-horse  power 
for  each  engine. 

The  steam  cylinders  of  each  are :  the  small  or  high-pressure  cylinder,  28 
inches  diameter,  and  5  feet  6  inches  stroke  ;  the  large  cylinder,  46  inches  diam- 
eter, and  8  feet  stroke. 

The  pump  is  in  each  case  a  plunger  and  bucket  pump  ;  the  barrel  24-inch 
diameter,  the  plunger  17^-inch,  and  the  stroke  7  ft.  1  inch. 

The  delivery  pipes  of  the  pumps  unite  on  one  pipe  main.  There  are  two 
air  vessels  to  each  pair  of  engines,  connected  with  the  delivering  pipes. 

Any  dimensions  or  details  given  by  me  of  engines  in  this  report,  were  de- 


THE  CHELSEA  WATER  WORKS.  31 

rived  from  the  foreman  or  the  engineman  in  charge.  The  precise  forms  and 
plans  of  these  pumping  engines  must  be  sought  for  in  other  works.  The  gen- 
eral characteristics  only  are  aimed  to  be  given  here. 

These  engines  cut  off  on  the  small  cylinder  at  half  stroke — steam  38  to  40 
Ibs.  The  engines  make  12  to  14  revolutions  per  minute,  varying  with  the  city 
consumption.  The  pumps  were  stated  to  deliver  120  to  126  gallons  per  double 
stroke. 

The  beam  of  each  engine  is  double,  composed  of  two  flitches,  32  feet  in 
length  between  end  centres,  and  five  feet  in  depth  at  its  bearings.  The  first 
built  engines  were  not  precisely  balanced.  To  remedy  this  in  the  pair  just  built, 
the  beam  is  made  heavier  on  the  side  towards  the  steam  cylinders  than  on  the 
other  side.  The  beams  of  the  other  engines  are  having  balance  plates  added  to 
them  inside,  at  the  same  end,  to  perfect  their  adjustments. 

The  one  fly-wheel  to  each  pair  has  a  diameter  of  18  feet,  weight  14  tons. 
The  suction  valve  of  the  pump  is  a  two-ring  valve.  It  is  in  fact  a  four-beat 
valve  of  the  same  character  as  the  Harvey  &  West  valve,  except  that  in  this 
case  the  beats  are  upon  the  same  plane,  and  the  facilities  of  emission  for  the 
water  are  therefore  not  so  good  ;  the  two  rings  are  not  connected,  but  act  inde- 
pendently of  each  other.  The  delivery  valve  is  a  flap  valve,  consisting  of  two, 
and  sometimes  three,  inclined  iron  flaps,  hinged  at  the  upper  end,  and  beating 
on  leather  linings. 

For  the  first  two  pair  of  engines  (A.  B.  and  C.  D.)  there  are  13  boilers  in 
one  house.  One  of  these  pairs  was  at  work  to-day  with  six  of  these  boilers  un- 
der steam. 

The  steam  carried  varied  from  40  to  42  Ibs.  pressure.  The  boilers  are  all 
of  the  Cornish  type,  single-flued,  the  shell  5  feet  10  inches  diameter,  the  flue  39 
inches,  length  30  feet.  Ten  boilers  are  used  when  both  pairs  of  engines  are  at 
work.  The  steam  pipe  connecting  all  these  boilers,  and  running  into  the  engine- 
house,  was  of  14  inches  diameter. 

The  fuel  used  is  the  slack  of  Newcastle  coal  (bituminous). 

The  last  built  pair  of  engines  (E.  F.)  has  a  battery  of  seven  boilers.  Five 
of  these  were  in  use  to-day.  They  are  Cornish  boilers,  single  flue.  Shell  5  feet 
10  inches  diameter,  flue  38  inches  ;  length  32  feet,  carrying  42  Ibs.  steam. 

There  are  two  large  square  chimneys  here  of  110  feet  in  height ;  I  was  not 
able  to  ascertain  the  sizes  of  the  flues. 

This  class  of  engine  has  now  been  long  and  well  tried  at  these  works,  and 
its  performance,  so  far  as  duty  trials  are  comparative  evidence,  has  proved  to  be 
at  least  equal  to  that  of  the  best  Cornish  engines. 

At  the  time  of  my  visit  two  pairs  of  engines  were  at  work  (A.  B.  and  E. 
F.)  pumping  into  the  same  rising  main,  which  is  of  30-inch  diameter,  and  con- 
veys the  water  to  the  Putney  reservoir,  distant  six  miles.  It  is  not  considered 


32  THE  CHELSEA  WATER  WORKS. 

safe  to  work  the  three  pairs  of  engines  into  the  same  main,  and  until  a  second 
main  is  laid,  one  pair  of  engines  will  always  be  at  rest. 

The  Company  is  laying  a  second  30-inch  main  at  this  time. 

The  filtered  water  is  all  pumped  into  the  Putney  reservoir,  with  the  excep- 
tion of  a  small  portion  which  is  drawn  from  the  rising  main  to  supply  the  inter- 
vening villages. 

From  the  Putney  reservoir,  the  City  district  pertaining  to  the  Company  is 
supplied  by  gravitation. 

The  Putney  reservoir  stands  181  feet  above  the  pump  well ;  at  the  time  of 
iny  visit  the  gauge  in  the  engine-houses  showed  a  pressure  of  220  feet. 

The  A.  B.  engines  were  making  14  to  14^  revolutions  per  minute,  and  the  E. 
F.  engines,  12  revolutions.  Both  pairs  of  engines  were  stated  to  be  working 
continuously  through  the  24  hours,  and  every  day  of  the  week.  It  has  been 
usual  for  two  pairs  to  work  during  the  day,  and  one  pair  at  night,  but  the  in- 
creased demand  for  water  this  season  must  lower  the  Putney  reservoir  during 
the  day  much  more  than  heretofore. 

Under  any  circumstances  the  water  in  the  rising  main  is  never  supposed  to 
come  to  a  state  of  rest,  but  the  rate  of  flow  during  the  day  is  generally  much 
more  rapid  than  during  the  night. 

During  the  night  hours  the  supply  of  water  is  cut  off  from  the  city  tene- 
ments, with  the  exception  of  factories  or  other  works,  where  the  necessary 
supply  of  water  cannot  be  continuously  maintained  by  cisterns.  The  main 
pipes  must,  therefore,  be  always  charged. 

The  Putney  reservoir,  which  is  covered,  has  a  capacity  of  8,300,000  gal- 
lons. There  is  a  small  open  reservoir  near  it  for  unfiltered  water,  with  a 
capacity  of  about  1,250,000  gallons. 

The  water  for  fire  purposes,  and  for  street-washing,  is  not  filtered.  Two 
small  engines  deliver  this  water  into  the  small  open  reservoir  above  mentioned, 
whence  it  is  passed  into  the  city  by  a  separate  system  of  distributing  pipes. 
The  engines  for  this  service  are  single  cylinder  rotative  engines,  with  a  fly- 
wheel to  each.  They  are  arranged,  however,  so  as  to  be  coupled,  and  generally 
work  in  connection.  The  steam  cylinder  of  these  engines  is  20  inches  diameter, 
with  a  stroke  of  36  inches.  The  pumps  are  plunger  and  bucket  pumps.  The 
pump  barrel  is  Ilk  inches  diameter,  with  30-inch  stroke. 

The  delivery  of  unfiltered  water  is  very  light  in  winter,  but  may  sometimes 
reach  500,000  gallons  per  diem  in  summer. 

The  pipe  main  conveying  the  unfiltered  water  to  the  Putney  open  reservoir, 
is  of  15  inches  diameter,  and  51  miles  in  length. 

There  are  a  pair  of  small  engines  (15-horse  power)  for  the  drainage  service 
— that  is,  for  pumping  off  the  low  refuse  water,  when  required,  from  the 


THE   CHELSEA   WASTER   WORKS.  33 

settling  basins,  and  we  presume,  also,  for  draining  off  the  water  from  the  sand 
of  the  filter  beds,  when  they  require  cleansing. 

These  works  have  been  constructed  from  the  designs  and  directions  of  Mr. 
James  Simpson,  Civil  Engineer,  under  whose  charge  they  continue  now.  Mr. 
Simpson  is  understood  to  be  the  originator  of  the  very  simple  and  manageable 
sand  filter  which  has  been  so  successfuly  used  at  the  London  Works  and  else- 
where. 


34  LAMBETH  WATER  WORKS. 


LAMBETH  WATER  WORKS. 


The  Lambeth  Works  are  situated  on  the  right  bank  of  the  Thames,  imme- 
diately above  the  Chelsea  Water  Works.  They  are  under  the  charge  of  the 
same  engineer,  Mr.  James  Simpson. 

There  are  four  filter  beds  here,  each  of  the  same  size  and  form,  as  may  be 
seen  in  the  accompanying  sketch  (Plate  5),  where  they  are  marked  a1,  a2,  a3,  a4. 

The  outer  walls  of  these  filter  beds  are  vertical  brick  walls,  thrown  into 
the  curved  forms  for  strength. 

The  central  wall,  which  appears  to  divide  each,  is  a  buttress  wall,  built  to 
receive  the  thrust  of  the  horizontal  arch  walls,  and  arranged  so  as  not  to  inter- 
fere with  the  free  passage  of  water  from  the  one  half  to  the  other. 

These  filter  beds  have  been  doubled  in  size  within  the  last  two  years.  The 
sand  area  of  each  filter  bed  is  16,500  square  feet,  now  making  for  the  four  beds 
an  aggregate  of  66,000  square  feet. 

These  works  were  reported  in  July,  1868,  to  be  delivering  that  month  an 
average  of  11,210,400  per  diem),  the  whole  of  this  water  passing  through  the 
filter  beds. 

Two  pairs  of  engines  were  at  work  on  the  day  of  my  visit,  making  15 
revolutions  per  minute. 

At  this  rate  I  calculate  their  delivery  to  be  about  453,000  gallons  per  hour, 
which,  applied  to  the  filtering  surface,  gives  a  flow  through  the  filters  of  6.86 
gallons  per  square  foot  per  hour,  when  the  four  beds  are  in  use,  and  in  a  ser- 
viceable state. 

The  average,  as  already  stated,  should  not  exceed  3.12  gallons  (2  cubic 
foot)  per  square  foot  per  hour. 

The  rate  here  is  therefore  more  than  double  the  usual  velocity,  but  this 
defect  is  to  a  certain  extent  compensated  by  an  auxiliary  filtration  which  the 
water  undergoes  at  the  settling  reservoirs. 

These  works,  which  at  my  previous  visit  in  1866,  possessed  no  settling 
reservoirs,  have  now  one  settling  reservoir  in  use,  and  two  under  construction. 

The  three  when  finished  will  have  a  water  surface  of  3.1  acres.  The  sub- 
joined plan  (Plate  5)  will  show  the  position  of  these,  and  of  the  filter  beds.  To 
remedy  the  inadequate  surface  area  of  the  latter,  a  vertical  filter  of  fine  gravel, 
designated  on  the  plan  as  "rough  filter,"  is  constructed  across  the  lower  end  of 


LAMBETH   WATER   WORKS.  35 

each  settling  reservoir.  This  gravel  is  held  in  place  by  two  brick  walls,  bolted 
together  at  intervals.  The  walls  are  4  feet  apart,  and  the  screen  of  gravel  is, 
therefore,  4  feet  thick,  by  about  15  feet  in  height,  and  150  feet  in  length.  The 
bricks  are  laid  slightly  apart  at  the  joints,  to  permit  the  water  to  reach  the 
gravel  and  to  escape  from  it  on  the  other  side. 

The  arrangement  will  be  understood  on  inspection  of  the  plan. 

That  this  rough  filter  was  operating  to  some  purpose  seemed  evident  from 
the  fact  that  the  water  stood  18  inches  lower  on  the  one  side  of  this  filtering 
wall  than  on  the  other. 

Doors  are  arranged  on  the  upper  side  for  drawing  off  the  gravel  at  intervals 
and  cleaning  it. 

The  bottom  of  each  settling  reservoir  consisted  of  a  layer  of  concrete 
resting  on  clay,  over  which  was  a  paving  of  brick  on  edge,  laid  in  mortar. 
The  side  slopes  were  1  to  1,  laid  in  the  same  way. 

The  water  is  drawn  directly  from  the  river  into  these  settling  reservoirs,  at 
the  upper  end  of  each,  passing  through  the  whole  length  in  each  case,  before 
reaching  the  filtering  walls.  There  are  screens  and  sluices  in  the  entrances  from 
the  river. 

Three  of  the  filter  beds  were  in  use  at  the  time  of  my  visit  (7th  August, 
1868),  the  fourth  had  just  been  cleansed.  One  f-of  the  filters  was  said  to  be 
cleaned  every  ten  days.  There  was  4  feet  of  water  on  the  beds. 

The  materials  of  the  filters  are  the  same  as  on  the  Chelsea  bed,  and  the  re- 
lative arrangement  the  same,  but  the  mode  of  collecting  the  clean  water  is 
different.  On  the  floor  of  the  new  portions  of  the  Lambeth  filter  bed  a  series 
of  small  brick  arches  is  built,  as  shown  on  the  cross  section  (Plate  5). 

These  arches  have  vertical  openings  in  them  across  the  axis  of  each, 
of  1  inch  in  width  on  every  27  inches  in  length  of  each  arch.  This  allows 
the  water  to  pass  through,  without  drawing  with  it  any  of  the  shingle.  The 
water  has  thus  but  a  short  distance  to  travel,  to  reach  a  collecting  drain. 

These  small  drains  deliver  into  a  larger  drain  communicating  with  the  out- 
side conduit  to  the  pump  wells. 

On  the  original  portions  of  these  beds  (the  halves  on  the  river  side)  small 
square  drains  are  in  use,  covered  with  slabs  of  slate  3  feet  long,  8  inches  wide, 
and  3  inches  thick. 

The  slabs  are  kept  an  inch  apart  and  covered  with  large  shingle.  These 
drains,  as  in  the  other  case,  deliver  the  water  into  the  central  collecting  drain. 
Some  fine  sand,  I  was  informed,  would  occasionally  get  through  the  shingle  into 
the  collecting  drains,  before  the  enlargement  of  these  filter  beds,  probably 
caused  by  the  unusual  rapidity  of  flow  through  the  filtering  materials,  which 
prevailed  then. 

The  depth  of  water  on  these  filters,  which  formerly  varied  with  the  stage 


36  LAMBETH  WATER  WORKS. 

of  the  river,  can  now  be  controlled  from  the  settling  reservoirs,  and  made 
uniform  or  otherwise  at  discretion. 

The  sand  removed  from  the  surface  of  the  filter-bed  (2  to  *  inch  in  thick- 
ness) during  the  process  of  cleansing,  is  washed  and  replaced  at  intervals.  The 
washing  here  is  done  by  using  hose  connected  with  a  pipe,  from  the  rising 
main. 

Eight  per  cent  of  the  sand  is  said  to  be  lost  by  the  washing  process. 
Twenty-four  inches  of  sand  is  taken  off  in  twelve  months,  by  the  various  cleans- 
ings.  It  is  ordinarily  replaced  but  once  a  year.  The  labor  of  attendance 
and  cleansing  of  the  filters  was  stated  (1866),  to  be  nearly  £1,000  per 
annum. 

There  are  six  double-cylinder  rotative  pumping  engines  working  in  pairs 
(3  pairs),  with  one  fly-wheel  to  each  pair.  The  third  pair  was  added  in 
1866-7. 

The  engine-houses  are  situated  about  600  feet  from  the  filter  beds.  The 
water  is  conducted  by  a,  conduit  to  the  pump  wells. 

The  engines  are  all  represented  to  be  of  the  same  dimensions,  viz. : 

The  small  steam  cylinder,  28  in.  diameter,  with  5'  6"  stroke. 
The  large     "  "        46  in.         "  8  feet     " 

The  pumps  are  plunger  and  bucket  pumps  ;  the  pump  barrel  24  in.  diam- 
eter, with  6'  11"  stroke  ;  the  pump  plunger  17!  inches  diameter. 

There  are  two  air  chambers  to  each  pair  of  engines,  10  feet  high,  by  38 
inches  diameter,  of  cast-iron  ;  they  are  connected  at  the  top.  There  is  no 
stand  pipe  here.  The  beams  are  all  double.  The  length  between  end  centres 
on  the  new  engines,  was  26  feet ;  the  depth  of  the  beam  at  the  gudgeon,  5'  6"; 
diameter  of  gudgeon  15  inches.  These  last  beams  were  made  heaviest  at  the 
steam  end,  sufficiently  so  to  balance  the  engine.  The  diameter  of  the  fly-wheel 
is  21  feet,  4  feet  cranks,  weight  15  tons. 

The  engine  was  cutting  off  at  one  half  on  the  small  cylinder,  and  making 
15  revolutions  per  minute. 

The  suction  valves  are  4-beat  valves,  in  two  rings  ;  these  valves  are 
weighted  to  make  them  work  well.  The  valves  of  the  new  engines  were 
striking  hard,  and  were  said  to  be  out  of  adjustment  as  regards  weight.  The 
delivery  valves  were  flap  valves  in  two  parts. 

For  the  six  engines  there  is  provided  a  battery  of  19  boilers,  all  connected. 
Twelve  boilers  were  in  use  to-day  for  the  four  engines  at  work. 

There  are  never  more  than  four  engines  at  work  at  present,  but  when  the 
second  force  main  is  laid,  the  three  pairs  of  engines  will  be  able  to  work  simul- 
taneously, if  necessary ;  the  second  main,  also  of  30-inch  diameter,  is  now  being 
laid. 


LAMBETH  WATER  WORKS.  37 

The  boilers  are  all  Cornish  boilers,  each  6  feet  diameter  of  shell,  and  31 
feet  long,  with  one  flue  39  inches  diameter.  The  fire  grates  6  feet  in  length. 
Every  boiler  has  a  large  drum  51  feet  high,  and  39  inches  diameter.  The 
steam  pipe  runs  over  the  drums,  and  is  15-inch  diameter. 

The  chimney  is  a  large  square  chimney,  100  feet  in  height,  and  apparently 
8  feet  square  inside. 

The  coal  used  is  Newcastle  slack. 

Four  engines  were  at  work  during  my  visit,  and  work  at  present  continu- 
ously, I  was  informed,  night  and  day.  They  all  pump  into  the  Brixton  reser- 
voir, through  a  rising  main  of  30  inches  diameter,  and  10i  miles  in  length. 

The  Brixton  reservoir  is  situated  103  feet  above  the  pump  well.  The 
gauge  showed  a  pressure  against  the  engines  of  190  to  192  feet.  At  night  the 
pressure  shows  200  to  210  feet,  the  difference  arising  from  the  relief  afforded 
by  two  or  three  branches  from  the  rising  main,  delivering  into  the  country  dis- 
trict, which  are  not  in  operation  during  the  night. 

From  the  Brixton  reservoir  the  water  is  distributed  to  that  portion  of  the 
district  which  it  controls,  the  remainder  being  pumped  up  from  that  point  to 
meet  the  requirements  of  the  higher  grounds  within  the  district.  The  reservoir 
is  covered  and  has  a  capacity  of  15,000,000  gallons,  with  12  feet  depth  of 
water. 

The  reservoir  falls  during  the  day  hours,  showing  the  consumption  of  water 
to  exceed  the  ordinary  rate  of  the  pumping  power.  It  is  filled  up  by  the 
pumping  engines  during  the  night  hours. 

At  this  reservoir  there  are  three  sets  of  supplementary  pumping  engines 
moving  portions  of  the  water  received  here  from  the  river  engines  to  higher 
altitudes. 

The  first  set,  consisting  of  two  engines,  pumps  the  required  supply  for  the 
Streatham  reservoir,  situated  82  feet  above  their  pump  well,  and  also  into 
Salthurst  reservoir,  situated  103  feet  above  their  pump  well.  An  18-inch  main 
connects  the  pumps  with  both  reservoirs,  the  length  to  the  Streatham  reservoir 
being  about  one  mile,  and  to  the  Salthurst  reservoir  about  5  miles.  The  Streat- 
ham reservoir  has  a  capacity  of  3,672,000  gallons  ;  the  Salthurst  reservoir,  of 
3,400,000. 

The  two  engines  are  each  double-cylinder  rotative  engines,  but  the  large 
cylinder  is  annular,  enveloping  the  small  one,  and  the  length  of  stroke  is  the 
same  for  both.  The  dimensions  were  given  me  as  follows  : 

Small  cylinder 16  in.  diameter  and  5'  6"  stroke 

Annular"        41  in.       "  "    5'  6"     " 

The  pump  is  a  plunger  and  bucket  pump,  the  barrel  17 is  inches  diameter, 

plunger  12ss,  stroke  4  feet  7g  inches. 

5 


38  LAMBETH  WATER  WORKS. 

But  one  engine  was  at  work. 

During  the  night  the  two  engines  are  at  work,  filling  the  reservoirs.  The 
engine  at  work  during  the  day  is  pumping  directly  into  the  appropriate  portion, 
of  the  district,  the  reservoirs  delivering  then  into  the  same  distribution  pipes. 

There  is  no  delivery  of  water  to  the  district  during  the  night  except  for 
fires,  and  for  any  manufacturing  works  that  may  require  a  continuous  delivery. 
The  day  delivery  is  intermittent,  the  turnkey  letting  on  the  water  so  many 
hours  to  one  portion  of  the  district,  and  so  many  hours  to  another.  The  same 
practice  prevails  in  the  Chelsea  district. 

Two  smaller  engines,  16  years  old,  deliver  into  the  Kockhill  reservoir,  which 
controls  and  supplies  the  highest  portion  of  the  district. 

The  Rockhill  reservoir  (covered)  has  a  capacity  of  1,250,000  gallons.  Its 
water,  when  full,  stands  247  feet  above  the  pump  wells  of  the  engines  which 
supply  it  (or  above  the  Brixton  reservoir). 

An  iron  tank  is  built  within  the  grounds  of  the  Rockhill  reservoir,  raised 
18  feet  above  its  level,  and  with  a  capacity  of  120,000  gallons. 

To  supply  a  small  portion  of  the  district  situated  above  both  of  these  last- 
mentioned  reservoirs,  there  is  a  stand-pipe  on  the  Rockhill  grounds,  which, 
when  in  use,  carries  the  water  50  feet  above  the  Rockhill  reservoir.  The  water 
is  pumped  over  this  stand-pipe  by  the  Brixton  pumps  so  many  hours  every  day. 

The  engines  referred  to  are  rotative  beam  engines,  usually  working  couplet, 
but  capable  of  working  independently.  There  is  a  fly-wheel  to  each.  But  one 
of  the  engines  was  at  work  at  the  time  of  my  visit. 

The  steam  cylinder  is  21  <z  inches  diameter,  with  36  inches  stroke.  The 
pump  is  a  plunger  and  bucket  pump,  the  barrel  12  in.  diameter,  plunger  82 
inches,  and  31  in.  stroke.  The  engine  makes,  according  to  circumstances,  22  to 
26  revolutions  per  minute. 

Another  pair  of  new  and  novel  engines  pump  into  the  same  high  service 
main  for  the  Rockhill  reservoir. 

These  are  rotative  beam  engines  coupled  to  one  fly-wheel,  the  steam  cylin- 
ders arranged  so  that  the  pair  forms,  in  effect,  one  double-cylinder  engine. 

There  is  a  plunger  and  bucket  pump  to  each  engine.  The  engines  and 
cylinders  stand  about  6  feet  apart,  centre  to  centre.  There  is  a  small  air  cham- 
ber to  each  engine.  The  pair  were  making  30  revolutions  per  minute.  The 
gauge  showed  a  pressure  of  316  feet. 

The  one  engine  has  a  steam  cylinder  of  12  in.  diameter,  with  36  in.  stroke  ; 
the  other  a  cylinder  of  21 2  in.  diameter,  with  the  same  stroke.  The  pump 
barrel  in  each  case  was  7i  in.  diameter,  with  31  k  in.  stroke. 

The  engines  were  said  to  work  very  economically  as  regards  fuel. 

The  delivery  of  water  by  the  Lambeth  Works  was  stated  to  average  in  1866 
9,000,000  gallons  per  diem,  exceeding  this  amount  considerably  during  the 


UNIVERSITY  OF 

OF  CIVH- 
BERKEL.EY.  CAUITORNlK 

LAMBETH   WATER   WORKS.  39 

summer  months.  All  of  this  water  passes  into  the  Brixton  reservoir,  with  the 
exception  of  the  small  portion  distributed  between  that  reservoir  and  the  river 
pumps. 

In  1849  the  delivery  of  this  Company  is  reported  to  have  averaged 
3,077,260  gallons  per  diem;  in  1855,  6,109,000  gallons  per  diem;  while  in 
June,  1868,  it  is  reported  at  10,607,300  per  diem. 


40  SOUTIIWARK   AND   VAUXHALL   WATER   WORKS. 


SOUTHWARK  AND  VAUXHALL  WATER  WORKS, 


The  water  for  the  district  supplied  by  this  company  is  taken  from  the  left 
bank  of  the  Thames  at  Hampton,  in  accordance,  with  the  law  which  requires  all 
the  Thames  water  companies  to  take  the  water  from  the  river  above  Teddington 
Lock.  But  the  principal  works  of  the  Company,  which  originated  when  London 
lay  entirely  to  the  east  of  them,  are  situated  at  Battersea,  on  the  right  bank  of 
the  Thames,  upwards  of  13  miles  from  Hampton.  Previous  to  1855,  the  Com- 
pany drew  its  water  from  the  Thames  at  Battersea.  The  pipe  main  connecting 
the  two  places  crosses  under  the  river  near  Richmond. 

At  Hampton  the  Thames  water  is  first  drawn  into  two  subsiding  reservoirs 
of  45,000  superficial  feet,  or  a  little  over  an  acre  each.  Three  sets  of  vertical 
iron  strainers  intercept  all  coarse  floating  matter. 

The  level  of  the  water  on  these  reservoirs  corresponds  with  the  water  in 
the  Thames.  They  are  calculated  to  hold  from  six  to  eight  million  gallons, 
according  to  the  height  of  the  river.  The  water  does  not  remain  at  rest  in  either 
reservoir,  nor  are  they  large  enough  to  admit  of  much  subsidence  taking  place 
at  any  time.  The  slow  movement,  however,  of  the  water  through  them  admits 
of  a  certain  amount  of  deposition,  and,  together  with  the  screens,  separates  the 
grosser  floating  matters  which  would  otherwise  reach  the  pumps.  The  existence 
of  two  divisions  admits  of  the  one  being  cleansed  while  the  other  is  in  service. 

A  36-inch  cast-iron  main,  1 3.07  miles  in  length,  transfers  the  water  from 
this  point  to  the  works  at  Battersea.  To  equalize  and  relieve  the  action  of  the 
engines,  the  water  is  pumped  into  a  stand-pipe,  the  rising  leg  of  which  is  135 
feet  in  height  above  the  reservoirs,  the  other  (the  down  leg)  65  feet  where  it 
connects  with  the  longer  leg.  The  pressure  on  the  pumps,  therefore,  cannot  at 
any  time  be  less  than  65  feet ;  at  the  time  of  my  last  visit  (5th  of  August,  18G8) 
the  gauge  showed  130  feet.  In  other  words,  the  head  required  at  that  time  to 
produce  the  required  flow  in  the  long  pipe  main  was  130  feet. 

For  this  duty  there  are  three  Cornish  engines  of  the  variety  called  "  bull 
engines."  Two  of  these  are  usually  at  work  night  and  day,  but  at  this  time,  in 
conseqaence  of  the  great  demand  for  water,  the  three  engines  were  at  work 
through  the  24  hours. 

The  engines  have  the  following  dimensions  : 

1.  Steam  cylinder  70  inches  diameter,  stroke  10  feet;  plunger  or  pole  42 
inches  diameter,  stroke  10  feet. 


SOUTIIWARK   AND   VAUXHALL    WATER   WORKS.  41 

2.  Steam  cylinder  66  inches  diameter,  stroke  10  feet ;  pump  pole  39  inches 
diameter,  stroke  10  feet. 

These  two  engines  were  (llth  of  June,  1865)  making  10  strokes  per  min- 
ute. 

3.  Steam  cylinder  60  inches  diameter,  stroke  10  feet ;  pump  pole  35  inches 
diameter,  stroke  10  feet. 

Engines  Nos.  1  and  2  have  air  vessels  on  their  branches  to  the  stand-pipe. 
All  the  engines  pump  into  the  stand-pipe.  The  three  engines  when  working 
together  (as  they  were  in  August,  1866)  were  controlled  by  one  cataract,  and 
averaged  then  9,780  strokes  in  24  hours  each,  equal  to  about  7  strokes  (6.8)  per 
minute. 

At  the  time  of  my  first  visit  they  were  making  from  9  to  10  strokes  per 
minute ;  during  the  day  hours  the  velocity  is  usually  greater  tlian  at  night. 
The  engines  were  cutting  off  at  two-thirds. 

The  suction  valves,  and  also  the  delivery  valves,  were  four-beat  valves,  of 
the  Harvey  &  West  pattern. 

For  the  three  engines  there  is  a  battery  of  nine  boilers,  all  of  which  were 
under  steam  to-day,  the  pressure  carried  varying  from  38  to  39  Ibs. 

They  are  all  Cornish  boilers  with  single  flues  ;  shell  5  feet  10  inches, 
length  28  feet,  flue  44  inches.  The  fuel  used  was  large  Welsh  coal  (bituminous). 

At  Battersea,  the  water  pumped  by  these  engines  through  the  long  36- 
inch  main  pipe,  is  received  into  two  subsiding  reservoirs,  one  of  270,000  square 
feet  (6.20  acres),  the  other  of  140,000  square  feet  (3.31  acres).  In  both,  9.41 
acres  ;  their  joint  capacities,  32*  million  gallons.  The  small  basin  was  empty 
at  the  time  of  my  visit,  undergoing  a  cleaning  out.  The  large  basin  was  full  of 
water,  the  depth  being  about  10  feet.  .  These  settling  basins  were  stated  to  be 
cleaned  out  once  in  two  to  four  months. 

The  water  from  Hampton  passes  into  these .  receiving  basins,  one  or  both, 
as  may  be  convenient,  and  from  thence  is  distributed  to  the  filter  beds,  of  which 
there  are  five.  The  water  has  no  opportunity  of  remaining  at  absolute  rest  in 
these  settling  basins,  but  the  slow  movement  through  them  admits  of  a  certain 
amount  of  deposition,  and  as  the  Thames  water  carries  but  little  sediment  in  sus- 
pension, except  in  floods,  the  process,  in  addition  to  what  occurs  in  the  Hampton 
basins,  is  ordinarily  sufficient  to  prepare  it  for  the  filter  beds.  Under  the  best 
summer  state  of  the  Thames  water,  the  filter  beds  would  operate  efficiently 
without  this  previous  preparation.  But  besides  that,  in  times  of  high  floods, 
when  the  river  is  very  turbid,  this  previous  process  of  deposition  of  the  grosser 
matters  is  most  important ;  it  is  at  all  times  valuable,  as  lengthening  the  time 
during  which  the  filters  continue  efficient,  and  economizing  the  process  of 
cleansing  the  sand  beds  and  the  cost  of  attendance.  The  history  of  the  different 
works  shows  a  growing  appreciation  of  the  advantage  of  large  settling  basins, 


42  SOUTHWARK   AND   VAUXHALL   WATER    WORKS. 

and  the  great  value  (in  insuring  at  all  times  a  perfect  nitration  as  well  as  in 
economizing  its  annual  cost)  of  this  preliminary  process. 

The  forms  of  the  settling  basins  and  filter  beds  are  shown  in  the  accompa- 
nying sketch  (Plate  6.) 

The  settling  basins  are  marked  B1,  B2.     The  filter  beds  c1,  c2,  c3,  c4,  c5. 

The  following  are  the  sand  areas  of  the  filter  beds  : 

c1,     31,000  square  feet. 
c2,     65,340      " 
c3,  130,000      " 
.    c4,     58,080      " 
c5,     94,000      " 

The  borders  of  the  filter  beds  and  settling  basins,  with  one  exception,  were 
sloped  at  the  rate  of  2  to  1,  and  covered  with  shingle.  One  of  them  has  a  brick 
vertical  wall  on  two  sides.  When  the  filters  are  bare  the  water  is  let  on  slowly 
from  above,  that  is,  upon  the  sand  surface  ;  and  the  attendant  averred  that  he 
had  no  difficulty  in  refilling  the  beds  in  this  way.  There  were  numerous  air- 
pipes  along  .the  tops  of  the  slopes  communicating  with  the  clear-water  drains 
below. 

A  shallow  open  drain  extended  from  the  one  end  to  the  other  of  the  filter, 
which  lay  bare,  the  tops  of  the  side  walls  of  which  were  level  with  the  sand  sur- 
face of  the  filter  bed.  In  refilling  the  filter,  the  water  is  let  into  this  drain  and 
flows  slowly  over  its  two  sides  upon  the  sand,;  it  is  obvious  that  if  the  sand 
surface  rose  slightly  from  the  drain  towards  the  outer  slopes,  the  filling  would 
take  place  without  producing  any  current  upon  the  bed  of  sand. 

The  materials  of  the  filters  were  stated  to  be  as  follows  : 

Sharp  river  sand 36  inches. 

Fine  gravel 12  inches. 

Screened  gravel 9  inches. 

Do.       rough  gravel 9  inches. 

Coarse  large  gravel ,    12  inches. 

.     78  inches. 

These  materials  rest  upon  a  floor  of  concrete. 

Small  drains  collect  the  water  in  some  of  the  beds  into  a  large  central 
drain,  and  perforated  pipes  in  others.  The  collected  water  is  conveyed  by  a 
conduit  to  the  pump  wells  of  the  several  pumps. 

There  is  no  reservoir  to  receive  and  store  up  the  filtered  water.  The  rate 
of  filtration  must  therefore  vary  with  the  rate  of  consumption. 

The  quantity  of  water  (all  of  which  passes  through  the  filters)  pumped  into 


SOUTHWARK   AND   VAUXHALL    WATER   WORKS.  43 

the  proper  district,  averaged  in  1867  about  13,000,000  gallons  daily,  but  during 
the  months  of  June,  July,  and  August  of  this  year  (1868),  it  has  increased  to  a 
consumption  of  about  15,000,000  imperial  gallons  daily.  Assuming  11  of  the 
15  millions  to  be  delivered  by  pumping  between  6  A.M.  and  6  P.M.  (there  being 
no  high  storage  reservoirs  connected  with  these  works),  the  rate  of  filtration 
with  one-fifth  of  the  filtering  surface  unemployed,  amounts  to  3.03  imperial 
gallons  per  square  foot  per  hour,  a  rate  of  velocity  through  the  filters  which 
corresponds  with  the  best  practice  ;  during  the  night  hours  the  rate  will  be  very 
much  less.  Each  filter  bed  was  stated  to  be  cleansed  off  once  in  two  months,  in 
the  ordinary  state  of  the  river,  and  once  in  two  to  four  weeks  when  the  river  is 
in  flood. 

There  are  six  pumping  engines  at  this  station,  all  of  the  Cornish  stamp  ; 
two  of  them,  however,  being  mongrel  in  that  respect,  having  double-acting 
pumps.  All  the  engines  are  beam  engines  except  one.  The  quantity  of  water 
pumped  daily,  all  of  which  passes  through  the  filter  beds,  exceeds  at  this  date 
(August,  1868),  15,000,000  gallons. 

There  are  two  separate  services  in  this  district — a  high  and  a  low  service. 
The  mass  of  the  water  goes  to  the  low  or  London  service  of  the  district. 

For  the  low  service,  four  engines  are  used,  and  were  all  at  work.  Towards 
night  two  are  kept  partially  at  work,  and  sometimes  three. 

The  four  engines  appropriated  to  the  London  service  work  through  two 
stand-pipes,  one  with  four  legs  and  the  other  with  three  legs. 

In  the  absence  of  any  one  at  the  works  who  could  explain  to  me  the  neces- 
sity of  so  many  pipes  or  legs.  I  have  had  to  assume  that  the  object  was  to  give 
stiffness  and  to  avoid  the  use  of  guys,  neither  set  of  stand-pipes  being  enclosed 
in  masonry. 

Both  sets  of  stand-pipes  have  but  one  up  leg,  the  others  are  down  legs  } 
the  junction  of  these  with  the  up  leg  is  at  the  same  height  in  both  cases,  viz., 
150  feet  above  the  pump  well,  but  the  pressure  gauges  in  the  engine-rooms 
showed  the  water  to  be  standing  at  165  feet  in  the  up  leg,  or  15  feet  above  the 
junction.  On  the  four-legged  stand-pipe  the  up  leg  was  of  48-inch  diameter, 
the  principal  down  leg  42-inch,  the  other  two  legs  of  28-inch  each.  The  fore- 
man of  one  of  the  engines  stated  that  the  large  down  leg  only  was  in  use  ;  the 
other  two  were  shut  off,  but  could  be  connected  if  desired. 

In  the  three-legged  stand-pipe  the  up  leg  is  of  28-inch  diameter  and  the 
principal  down  leg  the  same  ;  the  other  leg  is  of  12-inch  diameter,  and  whether 
used  or  not,  did  not  appear.  In  the  cases  of  both  stand-pipes,  the  legs  are  at 
intervals  tied  together  by  rods. 

The  general  dimensions  of  the  four  engines  referred  to  are  as  follows  : 


44  SOUTIIWARK   AND   VAUXHALL    WATER   WORKS. 

No.  1. — Single- Acting  Beam  Engine. 

Steam  cylinder  64  inches  ;  stroke  10'  6",  making  eight  strokes  per  minute. 
Pump  plunger   33  inches  ;   stroke  11'  6" ;  double  beam,  unequal,  5  feet 
deep  at  gudgeon.     Pumping  over  the  largest  stand-pipe. 
Small  air  chamber  between  engine  and  stand-pipe. 
Working  against  105  feet  head. 

No.  2. — Single- Acting  Beam  Engine. 

Steam  cylinder  112  inches  ;  stroke  10  feet,  working  close  to  9'  9".  6th 
August,  1868. 

Cutting  off  at  one-half;    8  strokes  per  minute. 

Pump  plunger  50  inches  ;   stroke  10  feet. 

Double  beam — length  32  feet  between  centres  ;  depth  at  gudgeon  8  feet ; 
diameter  of  gudgeon  18  inches. 

The  flitches  three  feet  apart  and  very  heavy.     Working  over  the  large  stand 

Pipe- 
There  is  a  small  air  chamber  outside,  of  48-inch  diameter. 

Pressure  by  gauge  showed  175  feet. 

No.  3. — Single- Acting  "Bull"  Engine. 

Steam  cylinder  70  inches  ;  stroke  10  feet ;  cutting  off  at  one-half  to  one- 
third  ;  making  8  to  9  strokes  per  minute. 

Pump  plunger  33  inches  ;  stroke  10  feet ;  working  over  the  smaller  stand- 
pipe  ;  pressure  about  165  feet. 

This  engine  usually  works  from  6  A.  M.  to  5=z  P.  M.,  and  also  from  12  P.  M. 
to  3  A.  M. 

No.  4. — Single- Acting  Beam  Engine. 

Steam  cylinder  68  inches  ;  stroke  10  feet ;  working  about  8  strokes  per 
minute. 

Pump  plunger  33  inches  ;  stroke  10  feet ;  working  over  the  smaller  stand- 
pipe. 

There  is  a  low  air  chamber  outside,  through  which  this  pump  probably 
works. 

Double  beam,  equal,  length  c.  c.  30  feet. 

Pressure  by  gauge  showed  165  feet. 

The  inlet  or  suction  valves  of  these  four  engines  are  four-beat  Husband 
valves.  Two  of  the  delivery  valves  were  stated  to  be  two-beat  valves  (Harvey 
&  West),  the  others  four-beat  valves. 


SOUTHWARK    AND   VAUXHALL    WATERWORKg.  45 

For  the  high  service  there  are  two  engines  which  I  shall  call  No.  5  and  No. 
6.  These  work  15  hours  of  the  day  each,  but  not  at  night,  unless  called  upon 
for  fire  purposes.  They  purnp  into  the  high  grounds  of  Wimbleton  and  Rich- 
mond. 

No.  5. — Single- Acting  Beam  Engine. 

Steam  cylinder  55  inches ;  stroke  8  feet,  making  12  and  sometimes  14 
strokes  per  minute. 

Double-acting  pump,  14s-inch  diameter  ;  stroke  8  feet.  The  pump  rod  is 
heavily  weighted  to  enable  the  engine  to  make  the  down  stroke. 

Double  beam,  length  c.  c.  25  feet. 

This  engine  is  not  connected  with  either  of  the  stand-pipes,  but  there  is  a 
weighted  plunger  on  the  main,  outside  of  the  house,  which  is  intended  to  afford 
the  same  kind  of  relief.  There  is  also  an  air  chamber  20  feet  high,  and  5  feet 
in  diameter. 

The  suction  valve  and  the  delivery  valve  are  both  four-beat  valves. 

The  pressure  by  gauge  showed  285  feet,  and  runs  up  at  times  to  305  feet. 

No.  6. — Single- Acting  Beam  Engine. 

Steam  cylinder  55  inches  ;  stroke  8  feet ;  making  10  strokes  per  minute. 

Double-acting  pump,  16-inch  diameter  ;  stroke  8  feet. 

The  pump  rod  is  weighted  sufficiently  to  produce  the  down  stroke. 

This  engine  does  not  work  into  a  stand-pipe. 

There  is  a  weighted  double-beat  valve  outside  to  relieve  the  main,  and  there 
is  also  an  air  chamber  between  this  valve  and  the  pump.  The  suction  valve  of 
this  pump  is  a  four-beat  valve,  and  the  delivery  valve  a  two-beat  valve. 

The  gauge  showed  the  pump  to  be  working  against  a  pressure  of  300  feet. 

The  above  six  pumping  engines  were  all  at  work.  There  are  no  storage 
reservoirs  to  meet  the  night  service.  A  certain  portion  of  the  engine  power  is 
therefore  always  at  work  through  the  night. 

To  supply  the  requisite  steam  for  the  six  engines,  there  are  25  Cornish 
boilers,  all  connected  so  as  to  form  one  battery,  so  to  speak. 

Twenty  of  these  boilers  were  in  use.  The  steam  showed  32  Ibs.  pressure 
in  the  engine-room. 

They  were  all  single-flued  boilers,  the  shell  6  feet  diameter,  the  flue  42 
inches,  the  length  30  feet. 

There  were  three  chimneys  to  the  25  boilers,  but  I  could  not  learn  their 

dimensions. 

6 


46  gOUTHWARK    AND   VAUXHALL    WATER   WORKS. 

The  average  daily  delivery  of  water  by  this  Company  was  reported  to  be  : 

In  1849 6,013,716  imperial  gallons. 

Inl855 10,331,122 

In  1865 : 12,180,000 

In  June,  July,  and  August,  1868. .  .  15,000,000 

This  Company  is  at  present  (August,  1868)  making  important  additions  to 
its  works  at  Hampton. 

These  additions  (now  under  construction)  will  consist  of  a  large  new  settling 
reservoir,  three  filter  beds,  and  two  pumping  engines. 

The  water  in  this  settling  reservoir  will  correspond,  like  the  others  here, 
with  the  level  of  the  water  in  the  Thames.  Screens  at  the  entrance  passage 
will  intercept  fish  and  floating  matter,  but  when  the  river  is  turbid  the  water 
will  not  be  so  well  prepared  for  the  filters  here  as  it  is  at  Battersea.  I  was  not 
able  to  obtain  a  diagram  plan  of  the  new  works  ;  but  the  accompanying  sketch 
will  give  an  idea  of  the  form  and  character  of  the  filter  bed  nearest  completion, 
without  being  absolutely  correct  in  dimensions.  (Plate  7.) 

The  sand  area  of  the  three  filters  I  estimated  at  about  54,000  square  feet, 
and  the  settling  reservoir  I, should  judge  to  be  about  two  acres  in  extent. 

The  sketch  (Plate  7)  of  the  filter  bed  and  cross-section  will  sufficiently  de- 
scribe its  characteristics. 

The  water  from  the  settling  reservoir  is  delivered  into  a  central  drain 
running  lengthways  of  the  bed,  having  a  collecting  drain  underneath  it,  to 
gather  the  clear  water.  On  the  side  walls  of  this  collecting  drain,  the  vertical 
joints  of  the  bricks  are  spaced  an  inch  apart  to  permit  the  filtered  water  to  pass 
into  the  drain.  There  are,  besides,  small  drains  laid  on  the  floor  at  right  angles 
to  the  main  drain,  and  delivering  into  it. 

These  small  drains  are  made  of  perforated  brick,  and  have  each  not  more 
than  4ij  inches  of  opening. 

The  floor  is  concrete  laid  upon  clay  ;  with  no  paving  over  the  concrete. 
The  side  walls  are  paved  with  brick  on  edge.  One  of  the  filters  was  about  half 
finished,  the  floor  and  slopes  entirely  so  ;  the  floor  was  tight  and  perfectly  dry, 
although  it  must  have  been  situated  nine  feet  below  the  level  of  the  adjoining 
river. 

The  filtering  material  is  composed  of  a  layer  of  large  shingle  on  the  floor, 
and  over  the  small  drains,  a  layer  of  smaller  shingle  over  that,  both  washed  and 
screened  ;  then  a  layer  of  coarse  gravel ;  and,  finally,  a  layer  of  fine  clear  river 
sand,  at  least  18  inches  thick. 

The  thicknesses  of  these  layers,  as  near  as  I  could  ascertain  them,  are  shown 
in  section.  (Plate  7.) 


SOUTHWARK   AND    VAUXIIALL   WATER   WORKS.  47 

There  are  three  12-inch  air  pipes  rising  from  the  central  drain  and  appa- 
rently no  others  ;  from  which  I  judge  that  it  is  intended  to  fill  the  filter,  when 
emptied,  from  below. 

In  the  bottom  of  the  tipper  or  open  portion  of  the  same  central  drain  are 
two  six-inch  clay  pipes,  with  caps  on  them,  probably  used  only  when  refilling. 

From  the  filter  beds  the  clear  water  will  pass  directly  to  the  pump  wells  of 
the  new  engine-house.  The  engine-house  is  arranged  to  receive  two  single- 
acting  beam  engines,  of  80-inch  cylinder  each ;  they  are  each  to  work  double- 
acting  pumps  with  solid  pistons ;  the  pump  rod  to  be  weighted  for  the  down 
stroke.  There  will  be  no  stand-pipe,  but  a  weighted  valve  on  the  branch  main 
of  each  pump. 

The  battery  for  these  two  engines  will  consist  of  eleven  Cornish  boilers  of 
the  same  size  as  those  in  use  at  this  station  (Hampton)  now. 

These  pumps,  when  finished,  will  deliver  the  water  filtered  at  this  station 
directly  into  the  high  grounds  of  Wimbleton  and  Richmond,  and  will  thus 
relieve  the  engines  at  Battersea  now  applied  to  this  service,  already  described 
as  No.  5  and  No.  6.  All  the  engines  at  Battersea  will  then  be  available  for  the 
low  service  of  this  district. 

The  high  grounds  of  Wimbleton  and  Richmond  lie  between  Hampton  and 
Battersea ;  at  present  the  water  passes  these  on  its  way  to  Battersea  to  be 
filtered,  and,  after  filtration,  is  returned  by  special  mains  to  these  high  grounds. 
The  new  works  will  save  this  roundabout  process  which  must  involve  considera- 
ble loss  of  power,  by  new  mains  connecting  the  new  Hampton  engines  in  the 
shortest  practicable  way  with  the  high  service  referred  to. 

I  was  informed  that  a  second  delivering  main  of  30  inches  diameter  was 
about  to  be  laid  between  the  Hampton  and  the  Battersea  stations. 

Mr.  Joseph  Quick  is  the  Engineer  of  this  Company. 


48  GRAND   JUNCTION    WATER   WORKS. 


GRAND    JUNCTION    WATER    WORKS. 


The  principal  works  of  this  Company  are  situated  at  Kew,  but  the  water  is 
obtained  from  the  Thames  river  at  Hampton,  about  8  miles  above  Kew. 

At  Hampton  there  are  two  subsiding  reservoirs  and  two  pumping  engines. 
.  The  water  flows  from  the  Thames  into  the  two  subsiding  reservoirs  through 
three  sets  of  iron  strainers  arranged  to  intercept  fish  and  floating  matters. 

The  reservoirs  are  of  the  same  size  as  those  of  the  Southwark  and  Vaux- 
hall  Works,  situated  on  the  same  bank  of  the  river  immediately  below,  viz.  : 
45,000  superficial  feet  of  area  each,  with  an  average  capacity  of  three  million 
gallons  each,  more  or  less,  varying  with  the  state  of  the  river. 

Each  reservoir  has  its  separate  communication  with  the  Thames  and  can  be 
used  separately. 

The  water  passes  slowly  through  the  reservoirs  to  the  pumps,  losing  in  its 
passage  a  certain  portion  of  any  matter  which  it  may  carry  in  suspension  in 
times  of  flood. 

There  are  two'  single-acting  "  bull "  engines  here  (Cornish)  of  the  same 
pattern. 

The  general  dimensions  of  each  are  : 

Steam  cylinder  60  inches  with  10  feet  stroke. 
Pump  plunger  42     "         "      10     " 

The  engines  were  cutting  off  at  half  stroke. 

Both  engines  are  working  continuously  at  this  date  (July,  1868)  night  and 
day,  and  have  not  been  able  at  all  times  sufficiently  to  supply  the  filter  beds  at 
Kew,  the  consumption  of  water  in  the  district  being  much  above  ,the  average 
this  season.  A  second  pipe  main  between  Hampton  and  Kew  will  in  a  measure 
correct  this  evil,  but  additional  pumping  power  will  also  be  wanted  at  Hampton 
shortly. 

There  is  a  stand-pipe  with  two  legs,  the  rising  leg  100  feet ;  the  down  leg 
connects  with  the  other  at  60  feet  above  the  pump  well.  These  legs  are  of  44 
and  33  inches  diameter  respectively. 

The  engines  were  working  to-day  (July,  1868)  against  a  pressure  of  91 
feet,  and  making  14  strokes  per  minute  the  two,  or  7  strokes  per  minute  each. 
The  strokes  were  made  alternating,  regulated  by  one  cataract. 


GRAND   JUNCTION    WATER   WORKS.  49 

There  is  but  one  air  chamber  to  the  two  engines. 

The  engines  deliver  into  a  33-inch  main,  82  miles  in  length  (Mr.  Mylne 
says  71  miles).  The  delivery  was  stated  to  average  11  million  gallons  daily. 
The  Registrar's  report  for  July  gives  the  average  as  11,121,734. 

The  calculated  rate  of  these  two  pumps,  allowing  5  per  cent,  for  loss  of 
action,  gives  a  delivery  of  11,515,140  imperial  gallons  in  24  hours.  The  pumps 
are  therefore  working  very  closely  up  to  their  capacity,  with  no  reserve  in  case 
one  of  them  should  get  disabled. 

This  shows  a  wonderful  perfection  in  the  machine,  and  a  dangerous  confi- 
dence we  might  add,  under  the  circumstances  of  this  exceptional  season. 

The  pipe  main  conveys  the  water  to  the  principal  works  at  Kew,  on  the 
same  side  of  the  Thames,  where  it  is  received  into  two  settling  reservoirs, 
either  of  which  can  be  used  separately.  The  two  reservoirs  have  a  joint  area  of 
245,000  square  feet  (5.62  acres). 

The  accompanying  sketch  (Plate  8)  will  explain  their  form  and  the  position 
of  the  filter  beds. 

The  water,  in  passing  slowly  through  these  settling  reservoirs  (marked  dl  d2 
on  the  sketch),  undergoes  a  certain  amount  of  deposition,  and  in  the  present 
state  of  the  Thames  river  (llth  June,  1866),  is  amply  prepared  for  the  filter 
beds.  The  water  in  the  settling  reservoirs  is  discolored  and  full  of  small  floating 
particles,  but  not  turbid.  After  filtration,  as  seen  in  a  glass,  it  is  clear  and 
sparkling. 

The  settling  reservoirs  are  said  to  be  cleansed  out  once  a  year.  They  will 
hold  11  to  12  feet  of  water,  but  in  July,  1868,  they  had  not  more  than  8  feet  of 
water  in  them. 

There  are  three  filter  beds  of  about  the  same  area  each,  marked  el,  e*,  ea  on 
the  sketch.  Their  joint  sand  area  was  stated  to  be  225,000  square  feet.  Two 
of  them  were  in  action  at  the  time  of  my  visit,  each  covered  with  about  two 
to  three  feet  of  water. 

Usually  there  is  sjx  feet  of  water  over  these  filters,  but  the  consumption  of 
water  during  this  hot  season  has  during  the  day  hours  somewhat  exceeded  the 
supply  from  Hampton,  which  has  the  effect  of  drawing  down  the  settling  reser- 
voirs, and  placing  a  shallow  body  of  water  upon  the  filters.  The  third  was 
uncovered  and  undergoing  the  process  of  cleansing. 

The  effect  of  the  shallow  body  of  water,  combined  with  its  temperature  this 
season,  which  was  sometimes  above  80°  Fahrenheit  in  the  Thames,  was  to 
encourage  a  very  delicate  vegetation  on  the  surface  of  the  filter  bed. 

This  vegetation  appeared  like  a  thin  green  carpet  of  velvet,  and  the  work- 
men were  rolling  it  off  in  strips,  at  the  time  of  ray  last  visit,  from  the  uncov- 
ered filter  bed.  It  was  manifest,  however,  that  the  filter  had  not  been  cleansed 
immediately  upon  its  ceasing  to  operate  as  such,  but  that  the  water  had  been 


50  GRAND   JUNCTION    WATER   WORKS. 

allowed  to  remain  upon  it  some  time  after  its  motion  downward  had  ceased  ;  in 
other  words,  when  it  had  ceased  to  change  and  had  begun  to  stagnate. 

The  two-thirds  of  the  filtering  area  in  use  amounted  to  150,000  square  feet, 
very  nearly. 

Conduits  from  the  underground  drains  of  the  filter  beds  conduct  the  water 
directly  to  the  purnp  wells  ;  there  being  no  intermediate  storage  basin  to  receive 
the  filtered  water,  the  flow  through  the  filters  must  vary  with  the  variations  of 
the  service. 

The  average  delivery  of  the  works  in  24  hours  being  9,800,000  gallons,  I 
will  assume  that  8  millions  are  delivered  during  twelve  hours  of  the  day.  This 
would  make  the  rate  of  filtration,  at  the  time  of  my  visit,  during  the  day  hours, 
equal  to  97  gallons  per  square  foot  per  diem  ;  when  the  three  filter  beds  are  in 
service  the  rate  averages  65  gallons  per  square  foot  per  diem.  At  certain  hours 
of  the  day  during  the  summer  months  it  considerably  exceeds  these  figures,  but 
during  summer  the  Thames  water,  except  after  heavy  rains,  is  usually  compara- 
tively clear,  and  the  chief  use  of  the  filter  beds  then  is  to  separate  it  from  all 
organic  impurities,  and  from  fish  of  all  sizes  and  descriptions. 

The  service  from  these  works  is  intermittent,  and  all  the  tenements  receiv- 
ing the  water  have  cisterns. 

There  is  a  high  storage  reservoir  connected  with  these  works  at  Camden 
Hill,  situated  120  feet  above  the  wells  of  the  pumping  engines. 

This  reservoir  by  its  auxiliary  pumping  power  supplies  a  high  district  of  the 
city  above  the  control  of  the  Kew  engines.  To  this  extent  it  loses  water  during 
the  day,  which  is  replaced  during  the  night  by  the  Kew  engines.  During  the 
day  the  Kew  engines  are  not  delivering  into  it.  It  is  a  covered  reservoir  of 
46,800  square  feet  water  area,  and  capable  of  holding  22  feet  of  water,  say  5 
million  gallons. 

This  reservoir  can  obviously  assist  in  meeting  any  sudden  requirements 
during  the  night  on  occasions  of  fires,  but  a  certain  portion  of  the  pumping 
power  is  always  held  in  hand  besides,  to  meet  the  emergencies  of  that  service. 

The  settling  reservoirs  and  filter  beds  are  bounded  by  brick  slope  walls,  at 
inclinations  of  2  to  1. 

The  filter  bed,  which  was  uncovered,  showed  an  open  drain  running  through 
its  axis,  the  side  walls  of  the  drain  being  carried  up  to  the  level  of  the  surface 
of  the  sand.  In  commencing  to  fill  this  filter  bed  with  water,  the  water  is  let 
into  this  drain,  and  overflows  from  it  on  either  side  slowly  upon  the  sand  sur- 
face. The  main  drain  for  the  collection  of  the  filtered  water  is  placed  imme- 
diately underneath  this  open  drain,  and  three  iron  12-inch  air  pipes  rise  from  it 
through  the  open  drain  to  a  height  above  the  full  water  of  the  filter  basin. 
From  this  main  drain  small  square  brick  drains  run  either  way  to  the  foot  of 
the  slopes,  and  from  the  ends  of  these,  small  air  pipes  of  1-inch  diameter  rise  to 


GRAND   JUNCTION    WATER   WORKS.  51 

•» 

the   top   of  the    slope   walls.     These    air    pipes    in   this   case   were    30    feet 
apart. 

The  materials  of  the  filter  beds  were  stated  by  the  attendant  to  be  as  fol- 
lows : 

Fine  sand 24  inches. 

Shells 3      " 

Gravel 24      " 

Pebble  stones 10      " 

61  inches. 

Covered  and  surrounded  by  the  last  are  the  small  brick  gathering  drains, 
laid  upon  a  floor  of  concrete. 

In  the  re.port  of  a  Board  of  Inspectors  made  in  1856,  the  filtering  medium 
is  stated  differently,  as  follows  : 

Harwich  sand , 3  to  4  feet  thick. 

Fine  gravel 1  foot  thick. 

Fine  screened  sand 9  inches  thick. 

Rough  screened  gravel 9  inches  thick. 

Coarse  gravel 1  foot  thick. 

This  gives  a  depth  of  filtering  material  of  78  to  90  inches.  The  washing 
of  the  sand  was  stated  to  cost  then  82  pence  (17  cents)  per  cubic  yard. 

The  filter  beds  are  cleansed,  I  was  told,  every  8  to  20  days  each.  The 
amount  of  sand  removed  does  not  exceed  half  an  inch,  and  this  is  washed  and 
laid  aside  to  be  replaced  at  intervals  of  6  months  or  more,  according  to  the  cir- 
cumstances of  the  service.  Two  circular  open  iron  tanks  are  used  for  cleansing 
the  sand.  They  have  each  a  false  bottom,  perforated  with  holes.  The  sand  is 
laid  upon  this  perforated  shelf,  and  water  under  a  high  pressure  being  connected 
below,  forces  its  way  through  the  holes  and  through  the  sand,  carrying  the 
muddy  particles  with  it,  and  flowing  off  until  clear,  over  the  sides  of  the  tank. 

There  are  four  pumping  engines  at  these  works  for  the  service  of  the  dis- 
trict, all  single-acting  Cornish  engines. 

Their  general  dimensions  are  as  follows  : 

No.  1. — Beam  Engine. 

Steam  cylinder,  90  inches  diameter  ;  11  feet  stroke. 

Pump  pole          38     "  "  11     

Weight  of  pump  pole,  45  tons. 

Walking  beam  30  feet  long  between  end  centres. 

Depth  at  centre,  5  feet. 


52  GRAND   JUNCTION    WATER   WORKS. 

This  beam,  however,  has  been  trussed  on  the  upper  side,  as  have  all  the 
others,  since  the  breaking  of  the  beam  of  No.  3  engine,  caused  by  a  chisel 
getting  upon  the  seat  of  the  suction  valve,  which  prevented  its  closing. 

Centre  gudgeon  16  inches  diameter. 

The  inlet  or  suction  valve  is  a  large  four-beat  valve  of  Husband's  patent ; 
the  delivery  valve  the  same.  There  is  an  air  chamber  to  this  engine,  but  it  was 
said  not  to  be  in  use. 

The  engine  was  cutting  off  at  one-third  and  making  six  strokes  per  minute 
(29th  July,  1868) ;  but  this  rate  varies  with  the  consumption  of  water. 

This  engine  pumps  over  a  stand-pipe,  the  rising  leg  of  which  is  42  inches 
diameter,  and  its  down  leg  30  inches.  The  junction  of  the  last-mentioned  with 
the  main  pipe  was  stated  to  be  170  feet  above  the  pump  well.  The  gauge  in 
the  engine-house  showed  a  pressure  of  165  feet ;  but  this  gauge  is  connected  with 
the  delivery  main,  at  a  point  which  I  should  judge  to  be  10  to  15  feet  above  the 
water  of  the  pump  well,  or  its  equivalent.  This  would  show  the  engine  to  be 
working  against  a  pressure  of  175  feet  or  thereabouts,  which  would  make  the 
water  stand  just  above  the  junction  of  the  two  legs  of  the  stand-pipe. 

There  are  two  stand-pipes  at  this  station  (built  in  1867),  both  enclosed 
within  the  same  tower,  which  is  of  brick,  and  square.  This  structure  is  18  feet 
square  inside,  with  a  narrow  iron  stairway  attached  to  the  walls,  and  carried  up 
to  the  top. 

The  stand-pipe,  mentioned  above,  is  the  largest  of  the  two  ;  the  other  has 

.  a  rising  leg  of  30  inches  diameter,  with  a  down  leg  of  21  inches  diameter  ;  the 

height  of  the  30-inch  leg  is  214  feet,  and  of  the  junction  point  of  the  down  leg, 

170  feet ;   hi  these  respects  the  same  as  the  larger  one.     A  waste-pipe  of  12 

inches  diameter  makes  a  fifth  vertical  pipe  within  the  tower. 

The  whole  five  are  constructed  from  cast-iron  pipes,  with  spigot  and  socket 
joints,  caulked  with  lead  in  the  ordinary  manner. 

The  Camden  Hill  reservoir,  already  mentioned,  is  not  connected  with  this 
engine,  nor  with  any  of  the  pumping  engines  at  this  station  during  the  day,  but 
during  the  night  two  of  the  engines  (usually  No.  1  and  No.  5)  pump  into  it  and 
replace  the  water  taken  from  it  during  the  day.  During  the  day  these  engines 
pump  directly  into  the  city  under  a  head  not  less  than  170  feet  and  varying 
to  185.  One  of  them  (usually  No.  4)  pumps  into  a  higher  service  than  the 
others,  against  a  pressure  of  212  feet. 

The  delivering  main  to  this  engine  is  30  inches  diameter,  and  its  length  as 
far  as  the  Camden  Hill  reservoir,  5  miles ;  but  its  branchings  and  extension  I 
have  no  means  .of  stating. 

The  engine  works  at  present  through  the  24  hours  and  every  day  of  the 
week. 


GRAND   JUNCTION    WATER   WORKS.  53 


No.  2.  —  Beam  Engine  —  Cornish. 

Steam  cylinder  64  inches  diameter  ;  stroke  8  feet. 
Pump  pole         24     "  "  "       8 


" 


Double-beam  26  feet  between  end  centres,  41  feet  deep,  trussed  on  upper 
side. 

Suction  valve,  a  four-beat  Husband  valve. 

Delivery  valve,  a  two-beat  valve. 

Suction  about  10  feet. 

There  is  one  air  chamber  to  this  engine  and  No.  3  ;  height  18  feet  ;  diam- 
eter 5  feet. 

Engines  No.  2  and  No.  3  work  directly  into  a  city  main,  but  have  a  throt- 
tled connection  with  the  stand-pipe  to  relieve  them  under  certain  circumstances, 
from  which  I  infer  that  they  are  serving  higher  ground  than  No.  1. 

The  engines  were  operated  by  one  cataract,  obliging  them  to  make  alter- 
nate strokes  in  equal  times.  They  were  each  making  11  strokes  per  minute 
and  cutting  off  steam  at  between  one-half  and  three-fourths. 

No.  3.  —  Cornish  Beam. 

This  is  a  duplicate  of  No.  2,  except  that  the  steam  cylinder  is  given  me  as 
of  63  inches  diameter. 

The  gauge  in  the  pump-room  showed  a  pressure  of  165  feet  on  the  deliv- 
ery pipe. 

The  two  engines  were  working  at  present  every  day  through  the  24  hours. 

No.  4.  —  Beam  Engine  —  Cornish. 

This  engine  has  a  steam  cylinder  of  65  inches  diameter  ;  in  other  respects 
its  dimensions  are  the  same  as  No.  2  and  No.  3.  It  was  working  into  a  higher 
service  against  a  pressure  of  21  2  feet,  having  a  throttled  connection  with  one 
of  the  stand-pipes.  It  does  not  work  at  night. 

There  is  an  air  chamber  on  its  delivery  main. 

No.  5.  —  Direct-Acting  Engine  —  Cornish  "Bull." 

Steam  cylinder  70  inches  diameter  ;  stroke  10  feet. 
Pump  pole         28     "  "  "       10    " 

This  engine  was  under  repair  at  the  time  of  my  visit  in  1868.  When 
working  it  makes  10  to  11  strokes  per  minute.  It  pumps  over  the  smaller  of 
the  two  stand-pipes  already  described,  under  a  head  ordinarily  of  175  feet, 
counting  from  its  inlet  water.  There  is  an  air  chamber  on  the  inlet  pipe,  30 

1 


54  GRAND   JUNCTION    WATER   WORKS. 

feet  in  height,  30  inches  diameter  at  bottom,  tapering  to  20  inches  at  top. 
There  was  a  value  attached  here  to  this  tapering.  The  inlet  pipe  connects  the 
pump  with  the  clear-water  well  of  the  filter  beds. 

This  engine,  when  at  its  routine  work,  pumps  during  the  day  into  the  city, 
and  at  night,  with  the  No.  1  engine,  refills  the  Camden  Hill  reservoir. 

The  water  valves  are  four-beat  Husband  valves. 

To  furnish  steam  for  these  engines,  there  are  twelve  Cornish  boilers,  all 
connected. 

Eleven  of  these  were  in  use  to-day,  all  the  engines  being  at  work,  except 
No.  5. 

Six  of  the  boilers  were  of  5  feet  6  inches  diameter,  length  28  feet,  with  a 
single  flue  in  each  of  40  inches  diameter. 

The  boilers  were  carrying  42  Ibs.  of  steam. 

The  fuel  used  was  Newcastle  slack  (bituminous).  There  was  but  one 
chimney  to  the  12  boilers,  apparently  about  120  feet  in  height. 

At  the  Camden  Hill  reservoir,  situated,  as  already  mentioned,  five  miles 
from  the  Kew  Works  and  120  feet  above  their  level,  there  are  two  pumping 
engines.  These  are  direct-acting  engines  of  the  "  Cornish  bull  "  variety. 

Their  general  characteristics  are  as  follows,  the  one  being  a  duplicate  of  the 
other  : 

Steam  cylinder,  70  inches  diameter  ;  stroke  10  feet.  Pump  plunger,  33 
inches  diameter  ;  stroke  10  feet. 

The  engine  was  making  10  strokes  per  minute.  Suction  valve,  four-beat 
Husband  valve.  Delivery  valve,  double-beat  Harvey  &  West. 

The  inlet  pipe  from  the  reservoir  to  the  engines  is  36  inches  diameter  ;  the 
delivering  main  30  inches. 

The  engines  work  over  a  stand-pipe,  serving  the  highest  grounds  of  this 
neighborhood. 

The  rising  leg  of  this  stand-pipe  is  48  inches  diameter  and  160  feet  in 
height ;  the  down  leg  is  36  inches  diameter,  and  connects  with  the  other  at  a 
point  90  feet  from  the  ground.  The  stand-pipe  is  enclosed  in  a  square  brick 
tower. 

The  gauge  in  the  engine-room,  which  is  connected  with  the  outlet-pipe, 
showed  a  pressure  of  100  feet,  which  rises  at  times  to  112  feet. 

Both  engines  were  at  work,  running  10  hours  a  day  (9  A.  M.  to  7  P.  M.), 
and  every  day  of  the  week. 

There  are  nine  Cornish  boilers  provided  for  the  two  engines ;  seven  of  these 
were  in  use  to-day  (30th  July,  1868).  The  boilers  were  each  6  feet  diameter 
in  the  shell,  and  30  feet  in  length,  with  a  single  flue  of  44  inches  diameter. 
They  carried  42  Ibs.  of  steam. 


GRAND   JUNCTION    WATER   WORKS.  55 

The  fuel  was  Newcastle  slack,  and  the  engines  were  stated  to  be  making  an 
average  duty  of  70  millions  to  112  Ibs.  of  coal. 

At  this  station  a  new  storage  reservoir  was  under  construction,  to  be  capa- 
ble of  holding  twelve  millions  imperial  gallons;  a  new  direct-acting  engine,  with 
a  steam  cylinder  of  90  inches  diameter,  was  also  under  progress. 

Mr.  Joseph  Quick  is  the  Engineer  of  this  Company ;  Mr. Fraser,  the 

Resident  Engineer. 


or 

OF  CML 

BERKELEY.  OJ-1FORNTA 


50  WEST    MIDDLESEX   WATER   WORKS. 


WEST  MIDDLESEX  WATER  WORKS, 


15th  June,  1866. 

The  principal  pumping-station  of  the  West  Middlesex  Water  Company  is 
situated  at  Hammersmith,  on  the  left  bank  of  the  Thames  ;  the  subsiding  reser- 
voirs and  filtering  works  lie  on  the  Barnes  side  of  the  river,  immediately  oppo- 
site. 

The  water  is  now  drawn  from  the  river  at  Hampton,  at  a  point  six  miles 
above  Teddington  Lock,  as  in  the  cases  of  the  Southwark  and  Vauxhall,  and 
the  Grand  Junction  AVater  Works. 

The  Hampton  station  of  the  Middlesex  Company  is  situated  immediately 
above  the  Grand  Junction  station.  There  are  no  preparatory  settling  basins  at 
Hampton  for  the  Middlesex  Works. 

The  water  is  passed  through  a  four  feet  conduit  from  the  river  directly  to 
the  pump-wells  ;  a  double  set  of  wire  screens  defends  the  mouth  of  the  conduit, 
and  prevents  the  passage  offish  and  all  floating  impurities. 

There  are  two  direct-acting  Cornish  engines  here  (Bull  engines).  They  are 
each  of  the  same  general  dimensions,  as  follows  : 

Steam  cylinder,  64  inches  diameter ;  stroke,  10  feet ;  plunger,  45  inches 
diameter ;  stroke,  10  feet. 

The  one  engine  was  at  work  (June,  1866),  making  10  to  11  strokes  pel- 
minute  ;  the  other  in  reserve. 

When  I  visited  the  works  in  July,  1868,  both  engines  were  at  work, 
operated  by  one  cataract,  so  as  to  make  alternate  strokes,  and  making  about  62 
strokes  each  per  minute  ;  the  pause  at  the  end  of  each  stroke  was  very  marked 
here. 

The  engines  were  cutting  off  at  one-third. 

The  suction  valve  is  a  four-beat  Husband  valve — a  great  improvement,  Mr. 
Hach  says,  on  the  double-beat  valve,  which  was  originally  in  use  here. 

The  delivery  valve  is  a  double-beat  valve. 

The  engines  work  over  a  stand-pipe,  the  down  leg  of -which  is  connected 
with  the  rising  leg  at  a  point  55  feet  from  its  base.  The  gauge  in  the  pump- 
room  showed  a  pressure  of  65  feet. 

The  engines  work  at  present  through  the  24  hours.  The  delivering  main, 
conveying  the  water  from  this  station  to  the  settling  reservoirs  at  Barnes,  is  36 
inches  diameter  and  nine  miles  in  length. 


WEST   MIDDLESEX  WATER   WORKS.  57 

The  delivery  in  July,  1868,  was.  reported  to  average  10,665,049  gallons 
daily  ;  in  June,  1868,  9,663,274  gallons. 

There  is  a  battery  of  nine  boilers  here,  but  three  of  them  were  being  re- 
placed by  new  boilers  ;  there  was,  therefore,  only  six  boilers  in  use.  These 
were  single-Sued  Cornish  boilers  ;  diameter  of  shell,  5'  9",  length  28  feet,  diam- 
eter of  flue,  42  inches. 

The  steam-pipe  connecting  all  was  of  18  inches  diameter.  There  were  two 
safety-valves  and  a  steam  alarm-whistle  to  each  boiler. 

The  pipe  main  crosses  the  river  at  Richmond,  and  delivers  the  water  into 
the  settling  reservoirs,  already  mentioned  as  situated  on  the  right  bank  of  the 
Thames,  at  Barnes,  opposite  to  Hammersmith. 

At  this  point  there  are  three  settling  reservoirs  of  9,  7  and  9  acres  area  re- 
spectively, making  25  acres  in  all.  And  there  are  five  filter  beds — four  of  1J 
acres  each,  and  one  of  21  acres  sand  area,  making  in  all  8k  acres  nearly,  or  358- 
000  square  feet,  strictly,  of  filtering  surface. 

The  water  is  delivered  at  option  into  either  of  the  three  settling  reservoirs, 
but  they  are  ordinarily  used  alternately  so  as  to  permit  a  deposition  in  still 
water,  in  each  case  of  10  to  30  hours,  according  to  circumstances.  In  the  clear- 
est state  of  the  river  water  this  settlement  in  still  water  is  hardly  necessary. 
It,  however,  always  reduces  importantly  the  work  to  be  done  by  the  filter  beds, 
and  economizes  very  sensibly  the  cost  and  time  expended  on  the  cleansing  of 
the  filters.  The  settling  reservoirs  contain  from  12  to  15  feet  of  water,  but  not 
exceeding  one-half  of  this  water  in  depth  can  be  drawn  off  on  the  filter  beds, 
and  these  settling  basins  are  not  contemplated  to  be  cleansed,  except  at  long  in- 
tervals. 

The  basins  are  bounded  by  slope-walls  of  stone,  sloped  at  1£  to  1. 

In  the  two  first  built  settling  basins  the  high  water  lines  were  but  2  to  3 
feet  above  the  full  water  of  the  filter  beds  ;  there  was,  therefore,  but  little  re- 
serve of  water  held  by  these  basins. 

In  the  last  built  basin  (g1}  the  full  water  stands  about  8  feet  above  the 
water  of  the  filter  beds. 

The  reserve  of  unfiltered  water  here  is  probably  about  20  million  gallons. 

From  the  settling  basins,  or  either  of  them,  the  water  is  drawn  at  discre- 
tion upon  the  filter  beds.  The  general  arrangement  of  these,  and  the  respective 
areas  of  the  basins  and  beds,  are  given  in  the  accompanying  sketch  (Plate  9), 
which,  however,  is  not  correct  as  to  scale,  the  authorities  having  declined  to 
permit  me  to  have  a  tracing  of  the  general  plan. 

In  this  sketch  the  settling  basins,  or  reservoirs  of  deposition,  as  they  are 
sometimes  called,  are  marked  g1,  g*,  g3 ;  the  filter  beds  are  marked  ft1,  ff,  h3,  A4 
and  h5. 


58  WEST    MIDDLESEX    WATER    WORKS. 

The  last  mentioned  and  latest  built  filter  bed  was  bare,  and  had  but  just 
been  cleansed. 

On  the  other  filter  bed  the  side  walls  are  vertical.  In  the  construction  of 
the  last  filter  bed  a  portion  of  the  old  settling  reservoir  (gl)  was  used,  and  the 
slope-walls  belonging  to  that  reservoir  were  retained.  This  filter  bed,  therefore, 
has  stone  slope-walls  instead  of  vertical  brick  walls,  as  in  the  case  of  the  others. 
An  open  brick  drain,  of  the  form  indicated  in  the  accompanying  sketch  (Fig.  1, 
Plate  9),  runs  through  the  centre  of  this  filter  bed,  used  only  in  re-filling  it  after 
it  has  been  laid  dry.  Its  side  walls  correspond  at  top  with  the  surface  of  the 
sand. 

Immediately  underneath  this  open  drain  there  is  a  brick  culvert,  2i  feet 
square,  for  collecting  the  filtered  water.  The  brick  side  walls  of  this  culvert  are 
half  dry  ;  half  of  each  brick  being  laid  in  mortar,  the  other  half  left  dry  to  permit 
the  entrance  of  the  filtered  water. 

From  each  side  of  this  culvert  drain-pipes  run  to  the  foot  of  the  slope- 
walls.  These  pipes  are  laid  20  feet  apart  c.  c.  They  are  six-inch  glazed  clay 
pipes,  perforated  with  three  rows  of  holes  on  each  side,  but  with  no  holes  on 
the  top  or  the  bottom.  These  pipes  are  bedded  in  the  large  screened  gravel 
which  forms  the  bottom  layer  of  the  filtering  materials.  The  water  is  let  on  to 
the  bed  by  means  of  the  open  drain  above  mentioned,  and  overflows  from  either 
side  of  it  upon  the  sand. 

The  filtering  materials  are  as  follows  : 

The  thickness  of  the  top  layer  of  fine  sand  varies  in  all  filters  during  the 
season,  for  the  half-inch  taken  off  every  two  or  three  weeks  during  the  process 
of  cleansing  is  usually  replaced  but  once  a  year. 

The  original  thickness  of  fine  sand  may,  therefore,  have  been  reduced  as 
much  as  1 2  inches  before  it  is  replaced. 

Fine  sand 21  inches  now — originally  33  inches. 

Barnes  sand 12      " 

Coarse    and    large    gravel  )  ~H.      (< 
screened  to  five  sizes . . .  ) 

60  inches. 

The  filter  beds  are  cleansed  alternately,  one  in  a  week,  or  in  three  or 
four  weeks,  as  the  state  of  the  river  water  may  require. 

The  sand  taken  off  is  cleansed  on  sloping  boards,  water  being  freely 
poured  on  this  incline.  Slats  are  nailed  across  these  boards  at  intervals,  to 
check  the  flow  of  the  sand,  and  allow  the  water  to  act  upon  it  sufficiently. 

The  eost  of  filtering  was  stated  by  the  engineer  to  be  about  ten  shillings 


WEST   MIDDLESEX   WATER   WORKS.  59 

per  million  gallons  (01.12  per  thousand  gallons,  or  about  one  quarter  of  a  cent 
per  thousand  gallons. 

While  there  is  an  average  rate  of  nitration  applicable  to  all  the  beds 
acting  jointly,  the  actual  rate  for  each  will  vary  with  the  condition  of  the  bed  ; 
the  61tration  being  quick  comparatively  when  it  is  clean,  becoming  more  and 
more  slow  as  it  gets  clogged  or  choked  with  sediment  or  other  matter. 

The  Engineer  of  these  works  considered  the  nitration  to  vary  on  any  one 
filter  from  6  gallons  per  foot  per  hour  to  liz  gallons  per  foot  per  hour — that  is, 
from  144  gallons  per  square  foot  per  day  to  36  gallons  per  square  foot  per  day. 

The  daily  delivery  of  water  to  this  district  was  stated  by  the  Engineer  to 
average  at  this  date  9?  million  gallons  per  diem  ;  but  there  being  no  storage 
basin  between  the  filters  and  the  pumps,  the  rate  of  filtration  must  vary  with 
the  service,  and  will  much  exceed  at  certain  hours  of  the  day  the  average  duo 
to  9J  millions. 

I  will  assume  that  during  certain  of  the  day  hours  the  water  passes 
through  the  filter  beds  at  the  rate  of  eight  million  gallons  in  twelve  hours. 
At  the  time  of  my  visit,  four  of  the  five  filter  beds  were  in  use,  covering  a 
sand  area  of  294,000  square  feet.  This  gives  an  average  of  54  gallons  per 
square  foot  per  diem  for  the  four  filters  jointly. 

The  clear  water  drains  are  carried  to  the  well  marked  K  on  on  the  sketch. 

From  this  well  two  pipes  are  carried  across  the  bed  of  the  river,  convey- 
ing the  filtered  water  to  the  different  pumping-engines. 

While  the  works  above  described  lie  on  the  right  bank  of  the  Thames 
the  pumping-engines  lie  on  the  left  bank,  close  to  the  river  at  Hammersmith. 

At  this  station  there  are  five  single-acting  (Boulton  &  Watt)  beam  en- 
gines, the  general  dimensions  of  which  are  as  follows  : 

No.  1. — Steam  cylinder,  54  inches,  stroke  8  feet ;  two  lifting-pumps,  one 
of  20-inch  diameter  and  8  feet  stroke,  the  other  15-inch  diameter  and  6  feet 
stroke,  averaging  14  to  16  strokes  per  minute. 

This  engine  was  at  work  pumping  into  the  distributing  main.  The  gauge 
showed  a  pressure  of  1  60  feet.  There  is  an  air  chamber  on  the  rising  main. 
There  is  no  stand-pipe  here  to  any  of  the  pumping-enginea. 

No  2. — Steam  cylinder,  54  inches  diameter,  8  feet  stroke  ;  pump  barrel,  20 
inches  diameter,  8  feet  stroke.  The  pump  piston  is  solid,  and  the  pump  is 
double-acting.  To  make  the  down  stroke  of  the  pump,  its  rod  is  loaded. 
This  engine  is  fifty  years  old.  It  was  npt  at  work  to-day  ;  it  works  alternately 
with  No.  1. 

This  engine  when  at  work  pumps  directly  into  the  distributing  main 
during  the  day,  assisted  by  the  high-storage  reservoir  at  Primrose  Hill. 

During  the  night,  when  the  service  of  the  district  is  not  in  action,  the 
engine  pumps  into  and  refills  the  Primrose  Hill  reservoir. 


60  WEST   MIDDLESEX   WATER   WORKS. 

The  Primrose  Hill  reservoir  has  a  capacity  of  4,752,000  gallons,  and  an 
altitude  above  the  pump-well  of  183  feet. 

The  capacity  of  the  Kensington  reservoir  is  3,500,000  gallons,  and  its 
altitude  above  the  pump-well  is  117  feet.  The  pipe  main  to  Primrose  Hill  is 
GT  miles  long,  and  from  30,  varying  to  36  inches  diameter.  The  main  to  Ken- 
sington reservoir  is  21  miles  long  and  21  to  23  inches  diameter. 

No.  3. — Steam  cylinder,  64  inches  diameter,  8  feet  stroke. 
Pump  barrel,       23       "  "         8     " 

The  pump-piston  is  solid  and  the  pump  double-acting,  the  pump-rod  being 
loaded  to  produce  the  down  stroke.  There  is  an  air  chamber  here,  but  no 
stand-pipe. 

There  is  a  weighted  safety-valve  on  the  pipe  main  outside  of  the  engine- 
house,  ingeniously  arranged  so  as  to  be  weighted  at  will  to  a  pressure  of  1 30 
i'ect  or  of  160  feet,  according  as  the  circumstances  of  the  service  require  it. 

No.  4. — Steam  cylinder,  72  inches  diameter,  stroke  10  feet. 
Pump-barrel,       23       "  "  "       10     " 

This  is  a  double-acting  pump,  the  pump-rod  being  loaded  as  in  No.  3. 
Not  at  work. 

No.  5. — Steam  cylinder,  80  inches  diameter,  stroke  10  feet. 
Pump-barrel,      24      "  "  "      10     " 

This  pump  also  is  double-acting,  being  loaded  like  the  others. 

.This  engine  is  at  work,  delivering  into  the  distribution  against  a  pressure 
by  the  gauge  of  162  feet. 

This  pressure  varies  with  the  service  from  150  to  190  feet. 

The  Kensington  reservoir  is  connected  with  and  sustains  the  low  service  of 
the  district.  The  Primrose  Hill  reservoir  is  confined  to  the  maintenance  of  the 
high  service. 

The  reserve  in  these  reservoirs  admits  of  the  district  being  supplied  for  a 
certain  time  without  the  aid  of  the  pumping-engines,  and  gives  time,  therefore, 
for  their  careful  maintenance  and  repair,  under  ordinary  circumstances. 

At  the  Primrose  Hill  reservoir  there  are  two  rotative  pumping-engines, 
raising  the  water  from  that  reservoir  to  certain  small  portions  of  the  district 
situated  above  its  level. 

No.  6  is  a  horizontal  engine,  with  crank  and  fly-wheel.  Steam  cylinder 
23  inches  diameter,  stroke  5  feet.  Horizontal  pump,  double-acting,  1 1  inches 
diameter,  with  stroke  of  5  feet.  This  engine  pumps  into  the  main  through  an 
air-vessel  ;  there  is  no  stand-pipe  here.  The  engine  was  making  25  revolutions 


WEST   MIDDLESEX   WATER   WORKS.  61 

per  minute.     It  works  12  to  15  hours  a  day.     The  highest  ground  served  is 
119  feet  above  the  engine. 

The  service  is  intermittent,  the  pressure  varying  according  to  the  parts 
served  from  119  feet  to  40  feet. 

No.  7. — In  this  engine  the  steam  and  pump  cylinder  are  vertical. 

Steam  cylinder,  23  inches  diameter,  5"  feet  stroke. 

Pump,  double-acting,  12       "  "         5     " 


« 


There  is  an  air  chamber  on  the  pipe  main. 

This  engine  was  not  at  work. 

The  average  daily  delivery  of  water  by  this  Company  was  reported  to  be 

In  1849 3,334,054  imperial  gallons. 

In  July,  1855 6,895,368 

In  1865 9,250,000        " 

And  now,  in  1868 10,000,000        "             " 

The  service  is  intermittent,  and  the  district  served  in  sections  ;  the  engines, 
therefore,  when  at  work  during  the  day,  are  pumping  against  a  varying  head. 

In  this  district,  there  is  no  separate  pipe  service  for  fire  purposes  and  street 
cleaning. 

Mr.  Wm.  B.  Hack  is  the  Engineer  in  charge  of  these  works. 

8 


62  THE   NEW   RIVER   WATER   WORKS. 


THE  NEW  RIVER  WATER  WORKS, 


June  13,  1866. 
August  8,  1868. 

THE  New  River  is  an  artificial  channel,  constructed  in  the  beginning  of  the 
17th  century,  with  the  view  of  supplying  London  with  water  from  springs  in 
Hertfordshire. 

It  was  begun  in  1608  and  finished  in  1613,  by  Sir  Hugh  Middleton. 

Although  the  New  River,  at  the  time  of  its  construction,  seems  to  have  had 
in  view  the  delivery  of  water  from  the  copious  springs  at  Chadwell  only,  it  now 
derives  the  mass  of  its  water  directly  from  the  River  Lea.  The  portion  derived 
from  springs  and  wells  at  present  does  not  exceed  22  per  cent,  of  the  whole. 

In  1857  the  Hampstead  Water  Works  district  was  incorporated  into  that  of 
the  New  River  Company  by  purchase. 

The  Company  makes  the  following  statement  of  its  sources  of  supply  : 

1st.  The  Chadwell  Springs  in  Hertfordshire. 
2d.  The  River  Lea. 

3d".  Deep  wells  on  the  line  of  the  New  River,  and  at  Hampstead  Heath  and 
Hampstead  Road. 

4th.  Small  springs  taken  into  the  river  in  its  course. 

5th.  Springs  at  Hampstead  and  Highgate,  collected  in  ponds  for  watering 
roads  and  other  such  uses. 

A  new  well  has  just  been  sunk  (August,  1868)  in  the  parish  of  Wormley,  near 
Cheshunt,  from  which  a  supply  of  2£  million  gallons  daily  is  expected  to  be 
obtained. 

The  Company  is  empowered  to  draw  water  from  the  Thames,  below  Black- 
friars  Bridge,  for  street  and  sewer  uses,  but  it  has  never  availed  itself  of  this 
power. 

The  average  delivery  per  diem  was  in  1866,  22,898,769  imperial  gallons,  of 
which  18,000,000  was  estimated  to  have  been  derived  from  the  River  Lea. 

During  the  month  of  July,  1868,  the  daily  average  amounted  to  27,140, 000 
imperial  gallons. 


THE   NEW   RIVER   WATER   WORKS.  63 

What  has  been  termed  the  New  River  is  a  very  crooked  canal  or  feeder, 
leading  from  Hertford,  in  the  valley  of  the  Lea,  to  the  centre  of  the  metrop- 
olis. 

Its  length  is  28  miles  (originally  39  miles),  of  which  25s  are  open  cut,  the 
remainder  consisting  of  pipes  and  tunnels. 

The  total  descent  on  this  distance  is  16  feet,  the  origin  of  this  feeder  near 
Ware  being  100  feet  above  Trinity  base,  and  its  terminus  at  Clerkenwell  (New 
River  Head)  84  feet  above  the  same  base. 

The  greater  part  of  the  New  River  water  is  derived  from  the  chalk  district 
of  Hertfordshire. 

Comparing  the  analysis  of  this  water  with  that  of  the  East  London  Water 
Works,  as  presented  in  the  city  pipe  mains,  the  portion  of  it  derived  from 
wells  seems  to  produce  no  perceptible  change  in  its  general  character. 

The  following  list  shows  the  reservoirs  pertaining  to  the  works  : 

Two  subsiding  reservoirs  at  Cheshunt, 18 k  acres 

Two         "  "  Hornsey, 8 

Two         "  "  Stoke .  Newington,  42i     " 

One         "'  "  Clerkenwell, 01     " 

Ponds  at  Hampstead  and  Highgate, 30       " 

The  amount  of  filtering  area  is  as  follows  : 

Three  filtering  beds  at  Hornsey, 2  acres. 

Five   '        "  "        Stoke  Newington, 5     " 

Three        "  "        New  River  Head,  Clerkenwell, ...    21" 

Two  just  finished  at  Stoke  Newington, 

one  only  in  use, 2     " 

There  are  covered  storage  reservoirs  at  Claremont  Square,  Maiden  Lane, . 
Highgate,   and    Hampstead,   the  joint    capacity  of  which  reaches  20  million 
gallons. 

The  drainage  area  of  the  River  Lea,  above  the  point  where  it  is  tapped  by 
this  Company,  comprises  284,160  acres,  or  444  square  miles. 

The  amount  of  water  which  the  Company  can  draw  from  the  Lea  is  limited 
to  22ij  million  gallons  of  its  natural  flow,  but  by  the  construction  of  reservoirs 
to  store  its  flood  waters  this  amount  can  be  increased,  in  the  opinion  of  the  En- 
gineer, by  10  million  gallons. 

There  are  seven  ponds  at  Highgate  and  six  ponds  at  Hampstead  Heath, 
from  which  a  separate  service  of  unfiltered  water  is  delivered  to  part  of  the 
district  for  street  watering  and  fire  purposes. 

Upon  the  line  of  the  New  River  the  Company  has  three  stations,  each  sup- 


64  THE    NEW   RIVER   WATER   WORKS. 

plying  separate  portions  of  its  large  district,  and  each  having  works  for  settling 
and  filtering  the  water,  besides  the  necessary  pumping-engines  for  delivering  it. 
These  are  the  Hornsey  Works,  the  Stoke  Newington  Works,  and  the  Works  at 
the  New  River  Head,  near  Sadler's  Wells. 

The  New  River  forms  the  feeder  to  each  of  these  works ;  the  overplus,  after 
supplying  the  lowest  works,  namely  those  at  Sadler's  wells,  passes  to  the  Thames 
by  means  of  a  48-inch  cast-iron  pipe. 

1st. — The  Station  at  Green  Lanes,  Stoke  Newington. 

At  this  place  there  are  two  settling  reservoirs,  the  one  of  20  acres  and  the 
other  22  acres  area. 

The  accompanying  sketch  (Plate  10)  will  explain  the  position  of  these,  and 
their  relation  to  the  filter  beds. 

The  settling  reservoirs  are  marked  ml  m?.  They  contain  an  average  depth 
of  15  feet  of  water,  but  only  3  feet  of  this  water  is  available  for  storage,  the 
remainder  being  below  the  level  of  the  filters. 

The  entire  flow  of  the  New  River  is  delivered  into  the  further  or  upper 
reservoir,  from  the  opposite  end  of  which  it  escapes  into  the  second  or  lower 
reservoir  (m2).  Prom  this  reservoir,  controlled  by  sluices,  it  is  drawn  off  as 
wanted,  into  the  lower  section  of  the  New  River  channel,  which  at  this  place  is 
carried  round  both  reservoirs,  and  can  be  used  independently  of  them  when 
needful.  Ordinarily  this  portion  of  the  channel  remains  in  disuse,  the  two 
settling  reservoirs  fulfilling  its  function  here,  as  well  as  encouraging  the  settling 
of  sediment  by  the  great  reduction  of  velocity  consequent  on  the  passage  of  the 
water  into  and  through  them.  ' 

The  channel  of  the  New  River  is  carried  thence  through  the  filtering 
grounds,  delivering  a  portion  of  the  water  upon  the  filter  beds,  and  conveying 
the  remainder  on  to  the  station  at  New  River  Head.  The  quantity  delivered 
upon  each  filter  bed  is  regulated  by  appropriate  sluices.  The  New  River  water, 
at  the  time  of  my  visit,  was  quite  turbid,  arising  from  some  work  in  progress 
on  its  banks.  This  turbidity  of  the  water  was  visibly  diminished  by  its  pas- 
sage through  the  two  settling-ponds.  • 

There  are  five  filter  beds  here  (July,  1866),  of  about  one  acre  each, 
marked  Nos.  1,  2,  3,  4,  and  5  on  the  sketch.  Three  of  these  measure 
300X150  feet  each,  and  the  other  two  315x135  feet  each. 

These  are  the  sand  areas  ;  the  filter  beds  have  brick  slope  walls  of  2  to  1. 
The  water  areas  are,  therefore,  larger. 

When  the  water  is  very  turbid,  two  of  the  filter  beds  have  sometimes  to 
be  cleansed  off  in  a  week  ;  when  it  is  in  a  good  state,  it  will  suffice  to  cleanse 
once  in  four  weeks. 

Two  new  filter  beds  have  just  been  added  (August,  1868),   one  only  of 


THE   NEW   RIVER   WATER   WORKS.  65 

which  is  in  use  ;  these  are'marked  No.  6  and  No.  7  on  the  sketch.  The  walls  of 
these  last  have  been  built  vertical,  and  therefore  the  sand  area  corresponds 
with  the  water  area. 

They  measure  each  300  by  140,  very  nearly,  or  about  one  acre  each. 

The  materials  of  the  filters  were  stated  to  be  as  follows  : 

Fine  sand,  originally 24  inches. 

(This  sand  is  allowed  to  be  reduced  to  12   inches 
before  being  renewed.) 

Coarse  sand 12 

Pea  shingle 12 

Shingle,  marble  size,  and  gravel 12 

60  inches. 

When  the  filter  bed  is  bare,  there  is  seen  a  cast-iron  semicircular  drain 
30-inch  diameter,  extending  from  the  river  bank  to  about  one-fifth  the  length  of 
the  filter  bed  on  its  centre  line.  The  lips  of  this  half-pipe  correspond  with  the 
surface  of  the  sand  of  the  filter. 

When  the  filter  bed,  after  being  cleaned  off,  has  to  be  refilled,  the  New 
River  water  (controlled  by  .a  sluice  in  the  brick  semicircular  well  shown  on  the 
sketch)  passes  into  this  half-pipe,  and  flows  over  either  side  of  it  upon  the  sand, 
slowly  covering  it  with  unfiltered  water.  After  the  bed  is  thoroughly  covered 
and  all  the  air  has  passed  off.,  the  water  is  allowed  to  flow  on  as  freely  as  the 
extent  and  condition  of  the  filter  may  require  it 

The  iron  drain  referred  to  is  supported  upon  iron  brackets. 

The  water,  after  passing  through  the  filtering  materials,  is  collected  by 
clay  pipe  drains  into  two  brick  drains,  placed  as  shown  on  the  sketch. 

These  brick  drains,  which  are  imbedded  in  the  shingle,  rest  on  the  bottom 
of  the  filter,  which  consists  of  a  brick  paving  on  edge,  set  in  mortar,  and  resting 
on  a  thick  layer  of  clay  puddle.  These  collecting  drains  deliver  the  filtered 
water  into  a  brick  culvert,  which  is  carried  along  the  river  bank  and  across  its 
channel  to  the  clear-water  well,  gathering  in  its  course  the  filtered  water  of  all 
the  filter  beds  in  operation. 

In  the  two  new  filter  beds,  built  in  1867-8,  the  arrangements  for  letting  on 
and  for  collecting  the  water  differ  somewhat  from  those  of  the  first  filters, 
described  above. 

In  those  last  filters,  the  side  walls  are  vertical ;  the  walling,  therefore,  must 
be  more  costly  than  the  slope-walls  of  the  old  filters,  but  the  entire  space  is 
made  available  with  the  vertical  walls,  while  a  considerable  portion,  when 
slopes  are  used,  is  useless  for  filtration  ;  there  is  always  danger,  too,  of  a 
portion  of  the  water  getting  behind  the  slopes  and  reaching  the  lower  drains 


66  THE   NEW   RIVER   WATER   WORKS. 

unfiltcred.     This   last  result  must  follow,   as  a  matter  of  course,  where  the 
slope-walling  is  laid  dry.     Here  the  slope-walls  are  well  laid  in  mortar. 

The  bottom  of  these  new  filters  consists,  as  in  the  others,  of  a  thick  layer 
of  clay  puddle,  over  which  is  laid  in  mortar  a  paving  of  brick,  on  edge. 

There  are  two  brick  drains  upon  this  floor  (running  longitudinally),  to 
collect  the  filtered  water  ;  but,  instead  of  having  clay  pipe  drains  at  right  angles 
to  these,  and  delivering  into  them  as  in  the  other  filters,  the  whole  floor  is 
covered  with  a  series  of  brick  drains,  laid  dry,  the  separating  walls  of  which  are 
one  brick  thick,  and  the  opening  of  each  drain  precisely  the  size  of  a  brick,  or 
about  k\  by  21  inches. 

This  arrangement  is  obtained,  as  shown  in  the  sketch  (Fig.  2),  by  laying  on 
the  floor  at  right  angles  to  the  main  drains,  rows  of  brick,  flat,  each  row  sepa- 
rated from  the  other  by  the  width  of  a  brick  ;  these  are  covered  by  dry  brick 
laid  in  the  opposite  direction,  as  close  as  they  can  be  laid.  Over  this  cover  the 
shingle  is  laid,  and  upon  that  the  gravel  and  sand,  the  same  as  in  the  other 
filters. 

These  small  brick  drains  deliver  each  by  suitable  openings  into  the  main 
collecting  drains,  which  again  deliver  into  the  collecting  conduit. 

The  unfiltered  water  is  delivered  upon  these  last  filter  beds  through  an  iron 
pipe  having  a  vertical  opening  in  the  centre  of  the  bed,  apparently  of  30  inches 
diameter. 

When  the  water'is  drawn  off  the  filter  for  cleansing,  the  refilling  of  it  is 
begun  from  below,  through  the  collecting  drains,  by  which  process  any  air  can 
always  be  more  surely  expelled,  and  the  refilling  executed  more  rapidly  and 
with  less  risk  than  where  the  filters  are  filled  from  above.  But,  in  this  case, 
the  water  used  for  refilling  until  the  surface  of  the  sand  is  covered,  should  be 
drawn  from  the  filtered  water.  Where  this  is  not  done,  the  unfiltered  water 
will  deposit  its  objectionable  qualities  throughout  the  filtering  materials. 

The  mode  adopted  for  collecting  the  filtered  water  here  is  the  most  perfect 
of  any  that  I  have  seen,  but  it  is  also,  I  should  judge,  the  most  expensive. 

The  water,  after  passing  through  the  materials  of  the  bed,  has  the  shortest 
practicable  space  to  travel  to  reach  a  collecting  pipe  or  drain  ;  there  will,  there- 
fore, be  little  or  no  risk  of  its  running  in  veins,  or  acquiring  velocity  enough  to 
carry  any  fine  sand  with  it,  as  may  sometimes  be  the  case  where  the  clay  pipe 
drains  performing  the  same  office  are  laid  twelve  feet  and  upwards  apart. 

The  average  amount  of  water  passing  in  24  hours  through  the  filters  was 
given  me  in  1866  as  from  12  to  14  million  gallons,  and,  judging  from  the  work- 
ing of  the  pumping-engines,  it  probably  doss  not  excaed  this  quantity  in 
1868. 

But  much  the  larger  fraction  of  this  amount  passes  through  the  filters  dur- 
ing the  day  hours.  The  pumping-engines  at  work  during  my  last  visit  (August 


THE   NEW   RIVER   WATER   WORKS.  67 

8,  1868)  were  delivering  at  the  rate  of  817,000  imperial  gallons  per  hour.  This, 
therefore,  was  the  rate  of  filtration  then. 

There  are  six  filter  beds  in  service  now,  the  seventh  remaining  at  present 
void  of  the  filtering  material.  These  six  filters  have  a  joint  area  of  262,000 
square  feet,  very  nearly. 

Assuming  one  of  these  filters  to  be  undergoing  the  cleansing  process,  there 
remains  say  218,000  square  feet  of  filtering  area  in  use,  which,  at  the  rate  of 
817,000  gallons  per  hour,  is  equal  to  3.75  gallons  per  square  foot  per  hour  (90 
gallons  in  24  hours). 

Before  the  last  filter  bed  was  added  the  rate  of  filtration  during  the  day 
must  have  sometimes  reached  4s  gallons  per  square  foot  per  hour.  Judging  by 
the  pumping,  it  must  vary  now  from  an  extreme  of  about  4  gallons  per  hour 
during  the  day,  to  2  gallons  per  hour  during  the  night. 

The  water  is  bright  and  clear  after  passing  through  the  filters. 

There  are  six  rotary  pumping-engines  here,  in  three  pairs,  with  a  fly-wheel 
to  each  pair.  The  engines  are. all  beam  engines,  and  the  pumps  are  all  plunger 
and  bucket  pumps. 

Four  of  these  engines  are  double-cylinder  engines,  of  like  size  ;  the  other 
two  are  single-cylinder  engines. 

The  following  are  the  general  dimensions  of  the  double-cylinder  engines  : 

Small  cylinder,  28  inches  ;  stroke,  5'6f". 

Large  cylinder,  46  inches  ;  stroke,  8'0. 

Double  beam,  length  c.  c.  24  feet ;  depth  at  centre,  5  feet. 

One  fly-wheel  to  the  pair,  24  feet  diameter. 

Pump  barrel  and  bucket,  27"  diameter  ;  stroke,  -6'H". 

Plunger,  20"  diameter. 

The  suction  valves  are  four-beat  valves,  but  not  the  Husband  valve.  The 
upper  half  moves  independently  of  the  lower  half;  the  seats  are  of  metal,  and 
bevelled  ;  the  delivery  valves  are  flap  valves,  having  each  two  hinged  flaps. 

The  pump  and  crank  rods  of  these  engines  are  made  up  of  wrought-iron 
plate  and  angle  bars,  very  neatly  rivetted  together. 

The  delivery  mains  are  of  20  inches  diameter,  but  they  are  connected  out- 
side with  a  larger  main.  There  is  an  air  chamber  upon  the  delivery  main  of 
each  pump,  15  feet  high  and  5  feet  diameter. 

These  mains  are  not  connected  with  the  stand-pipe. 

The  double-cylinder  engines  are  used  for  the  night  service,  and  are  rarely 
at  work  during  the  day,  probably  because  their  combined  pumping  capacity  is 
below  the  requirements  of  the  day  service  here. 


68  THE   NEW   RIVER   WATER   WORKS. 

They  work  into  the  Maiden  Hill  reservoir,  which  stands  115  feet  above  this 
station,  making  ordinarily  14  revolutions  per  minute. 

There  are  two  covered  reservoirs  at  Maiden  Lane,  having  a  joint  capacity 
of  14s  million  gallons  ;  they  are  distant  83  miles  from  the  Stoke  Newington 
station. 

The  pair  of  single-cylinder  engines  have  each  the  following  dimensions  : 

Steam  cylinder,  60-inch  diameter  ;  stroke,  8  feet. 

Outer-pump  barrel,  31]j"  diameter  ;  stroke  7  feet. 

Outer-pump  plunger,  22". 

Inner-pump  barrel,  43"  diameter  ;  stroke,  4'  9". 

Inner-pump  plunger,  SOa". 

Double  beam — length,  c.  c.  27  feet ;  depth,  6  feet. 

One  fly-wheel  to  the  pair — diameter,  25  feet ;  weight,  including  shaft  and 
crank,  00  tons  ;  making  14  to  14s  revolutions  per  minute. 

Suction  valve,  a  large  double-beat  valve. 

Delivery  valve,  a  four-flap  valve. 

There  is  a  stand-pipe  here,  into  which  the  inner  or  larger  pumps  work. 

The  rising  leg  is  of  48-inch  diameter,  the  down  leg,  42-inch.  These  legs 
have  two  connections,  one  at  87  feet  from  the  water  in  the  well,  and  the  other 
at  130  feet. 

The  connection  at  the  upper  end  is  made  by  an  iron  tank  ;  a  12-inch  waste 
pipe  is  arranged  to  carry  off  the  overflow  from  the  tank. 

These  stand-pipes  are  of  cast-iron,  in  9  feet  lengths,  with  socket  joints 
caulked  with  lead  in  the  usual  way.  They  are  protected  by  a  brick  tower,  in 
which  a  light  iron  stair-case  enables  the  workmen  to  reach  any  part  of  the 
pipes. 

The  lower  connection  only  has  been  used  thus  far.  The  engines  were 
pumping  over  this  junction  (87  feet),  but  the  down  leg  was  not  full  ;  on  the 
contrary,  the  water  at  the  time  of  my  visit  stood  in  it  at  60  feet  above  the  pump- 
well,  or  about  27  feet  below  the  junction.  I  presume  that  it  rises  to  the  junc- 
tion, or  above  it,  when  the  day  consumption  is  at  its  minimum. 

From  the  down  leg  of  the  stand-pipe,  a  36-inch  main  conveys  the  water 
to  the  district. 

The  small  pumps  of  this  pair  of  engines  work  through  air  chambers  into 
a  common  main,  which,  passing  round  the  outside  of  the  stand-pipe  tower, 
connects  outside  with  the  36-inch  main  above  mention-ed. 

These  pumps  at  one  time  worked  like  the  others,  directly  into  the  stand- 
pipe,  but  the  arrangement  has  been  changed  to  the  advantage,  it  is  said,  of  the 
machine. 

The  36-inch  main  is  connected  with  the  Pentonville  reservoir  at  Claremont 
Square,  which  stands  40  feet  above  this  station,  and  has  a  capacity  of  3 3  million 


THE   NEW   EIVER   WATER   WORKS.  69 

gallons.     The  main  acts  also  intermediately  as  a  distributing  main  ;  its  length 
was  given  me  as  2  2  miles. 

This  pair  of  engines  pump  every  day  of  the  week  except  Sunday,  their 
large  pumps  working  against  the  constant  head  of  87  feet,  which  the  stand-pipe 
imposes,  and  their  small  pumps,  against  the  varying  head  on  the  district,  which, 
during  the  day,  seems  to  average  60  feet,  all  delivering  into  the  one  main. 
To  supply  steam  to  the  engines  of  this  station,  there  are  two  batteries  of 
nine  boilers  each,  under  one  roof;  the  boilers  are  all  connected,  and  the  two 
batteries  are  also  connected,  so  that  the  boilers  of  the  one  or  the  other,  or  as 
many  of  them  as  may  be  wanted,  can  be  used  at  discretion. 

At  the  time  of  my  visit,  12  boilers  were  in  use  supplying  steam  to  the  pair 
of  single- cylinder  engines  then  at  work. 

The  boilers  have  the  following  dimensions  : 

Shell,  6  feet  diameter  ;  length,  31  feet ;  single  flue,  40  inches  diameter. 

About  one-third  of  a  mile  north  from  the  Stoke  Newington  Works,  but 
under  the  same  superintendence,  and  connected  with  the  same  filtered  water, 
there  are  two  reserve  engines,  used  only  in  emergencies. 

At  Tottenham  there  is  still  another  reserve  engine,  which,  in  an  emergency, 
can  be  connected  with  the  supply,  taking  its  water  in  such  case  directly  from 
the  river  Lea.  This  engine  was  described  to  me  as  a  single-acting  Boulton 
&  Watt  engine. 

Steam  cylinder,  60  inches  in  diameter  ;  9  feet  stroke. 

Pump,  44  inches  in  diameter  ;  9  feet  stroke. 

This  is  a  direct-acting  engine,  having  no  beam.  It  is  a  bull  engine,  so 
called,  except  that  the  steam  lifts  water  instead  of  lifting  a  plunger. 

2.  The  Hornsey  Station. 

At  this  station  there  is  a  settling  reservoir  and  three  filter  beds. 

The  settling  reservoir  has  four  acres  of  water  area,  with  a  depth  of  water 
from  15  to  20  feet.  Not  more  than  7  feet  of  this  water,  however,  can  be 
drawn  off  upon  the  filter  beds.  The  reservoir  has  been  four  years  in  use,  and 
has  not  been  cleansed  out  during  that  time.  A  sufficient  quantity  of  the  New 
River  water  is  let  into  this  reservoir  to  maintain  it  at  about  a  uniform  level. 
The  water  is  received  into  the  further  end  of  the  reservoir,  and  passes  through 
it  towards  the  filter  beds.  The  amount  of  water  used  at  this  station  does  not 
reach  probably  more  than  750,000  gallons  daily  ;  the  movement  must,  therefore, 
be  very  slow,  and  the  opportunity  for  deposition  considerable.  The  reservoir 
is  bounded  by  slope-walls  of  stone  paving,  at  2  to  1. 

From  the  settling  reservoir  the  water  is  let  at  will  upon  either  of  the  filter 
beds  by  appropriate  sluices. 

9 


70  THE    NEW    RIVER   WATER   WORKS. 

The  sand  area  of  each  filter  bed  measures  about  30,000  square  feet.  There 
are  90,000  square  feet  in  the  three  filter  beds.  The  sides  are  sloped  at  1  to  1, 
and  paved  with  brick. 

At  the  time  of  my  visit  there  was  abous  8  feet  of  water  upon  the  filters, 
and  all  three  were  in  use.  One  of  them  was  evidently  about  choked,  and  ready 
for  cleaning.  The  engine  was  pumping  at  that  time  at  the  rate  of  45,000 
gallons  per  hour.  There  is  also  a  water-wheel  at  this  station,  delivering  some 
water  to  the  neighborhood.  Making  allowance  for  the  action  of  this  last,  the 
rate  of  filtration  with  two  of  the  filter  beds  in  use  did  not  exceed  20  gallons 
per  square  foot  per  diem.  The  filtering  accommodation  here  is  at  present 
greatly  in  advance  of  the  requirements  of  this  section  of  the  district,  an  anomaly 
in  London  practice,  where  the  companies  find  it  difficult  to  keep  up  with  the 
rapidly  increasing  wants  of  the  population.  These  filter  beds  are  not  usually 
cleansed  out  more  than  once  in  two  or  three  months  for  each  bed,  at  present. 

The  materials  of  the  beds  were  stated  to  be  as  follows  : 

Sand  originally, 36  inches. 

Fine  screened  gravel 12        " 

Coarse  gravel  screened, 12        " 

60        " 

f 

Small  drains  of  brick,  on  edge,  with  perforated  brick  on  top,  are  used  for 
collecting  the  filtered  water.  The  bottoms  of  the  filter  beds  are  paved  with 
brick  on  edge,  set  in  mortar,  and  resting  on  the  natural  bottom,  which  is  clay. 

At  this  station  there  is  one  Cornish  beam-engine  delivering  the  filtered 
water  into  Hornsey  Lane  reservoir,  313z  feet  above  Trinity,  H.  W. 

The  steam  cylinder  is  44  inches  diameter  ;  stroke ....    10  feet. 
The  pump  plunger  is  15      "  "  "     9     " 

The  engine  was  making  11  strokes  per  minute,  and  the  gauge  showed  a 
pressure  of  300  feet.  It  was  said  to  be  delivering  630,000  gallons  per  diem, 
working  about  14  hours  a  day.  (1866.) 

At  Hornsey  Lane  reservoir  there  is  a  small  engine  of  50-horse  power,  that 
pumps  from  that  reservoir  over  a  stand-pipe  into  the  Hampstead  reservoir,  situ- 
ated 415  feet  above  the  Thames. 

The  two  last-mentioned  reservoirs  are  covered,  and  are  stated  to  have  a 
capacity  jointly  of  about  two  million  gallons. 

Within  the  Hornsey  ground,  and  on  the  line  of  the  New  River,  a  fall  of  four 
feet  here  is  utilized  by  a  breast-wheel  working  six  small  pumps.  This  wheel 


THE   NEW   RIVER    WATER   WORKS.  71 

works  15  hours  a  day,  delivering  about  100,000  gallons  daily.     The  water  is 
passed  over  a  stand-pipe,  the  head  of  which  is  70  feet  above  the  pumps. 

3.   The  Lower  Station  at  New  River  Head. 

There  is  a  small  circular  settling  reservoir  here  surrounded  by  three  filter 
beds. 

The  settling  reservoir  has  a  water  area  of  one  acre,  which  would  be  of  little 
account  were  the  water  entering  it  turbid  ;  but  its  passage  through  the  large 
reservoirs  at  Stoke  Newington,  together  with  its  slow  movement  through  the 
intervening  canal,  has  deprived  the  water  of  most  of  its  sediment  before  it  reaches 
this  point,  and  the  chref  duty  of  the  filters  consists  in  separating  any  remains  of 
organic  matters. 

The  three  filter  beds  have  a  joint  area  of  2*  acres  (108,900  superficial  feet). 
They  were  all  covered  at  the  time  of  my  visit  with  from  3  to  4  feet  of 
water,  but  one  of  them  was  ready  for  cleaning,  and  must  have  been  filtering  at 
a  very  slow  rate,  if  any. 

The  materials  of  the  filter  beds  are  sand  and  gravel  ;  there  are  from  24  to 
30  inches  of  fine  sand,  and  30  inches  of  screened  gravel,  the  fine  gravel  being 
placed  near  the  sand,  and  the  coarse  and  large  gravel  at  the  bottom.  Earth- 
enware drain  pipes  collect  the  water  into  a  central  culvert,  which  again 
conveys  it  to  a  well,  whence  it  is  connected  with  the  pumps. 

The  drain  pipes  are  seven  inches  wide  at  bottom,  and  eight  inches  high. 
On  the  bottom  they  are  flat,  but  on  the  top  semicircular,  as  shown  on  the  sketch. 
The  holes  or  perforations  are  confined  to  the  semicircle.  One  of  the  filters  is 
cleansed  ordinarily  once  in  three  weeks.  The  walls  of  the  filters  and  of  the  set- 
tling reservoirs  are  of  brick,  and  vertical. 

There  is  no  storing  basin  for  filtered  water  at  these  works.  At  the  time 
of  my  visit  the  pumps  were  judged  to  be  delivering  244,000  gallons  per  hour. 
Supposing  two-thirds  of  the  filtering  surface  to  be  in  action,  this  would  give  a 
rate  of  80  gallons  per  square  foot  per  diem. 

With  the  entire  filtering  area  in  useful  action,  which  can  rarely  happen,  the 
rate  would  be  54  gallons  per  square  foot  per  diem. 

There  are  two  Boulton  and  Watt  engines  here,  which  have  been  at  work 
since  1812. 

They  are  single-acting  beam  engines,  of  the  same  pattern,  each  working 
two  lifting-pumps. 

Steam  cylinder,  48  inches  diameter  ;  stroke,  8  feet 
Pumps,  one  of  29       "  "  "        8     " 

"      the  other  18      "  "  "        6     " 


72  THE   NEW   RIVER   WATER   WORKS. 

One  engine  was  in  action  making  14  strokes  per  minute.  The  other  was 
at  rest.  The  engines  work  three  month  shifts.  The  delivery  was  given  as  294 
gallons  per  stroke  of  the  two  pumps,  but  it  did  not  probably  exceed  275. 

The  pumps  work  into  separate  pipe  mains  over  a  stand-pipe  with  three  legs, 
with  a  small  cistern  where  the  bend  or  connection  would  otherwise  be.  One  leg 
takes  the  water  up,  another  down,  and  a  third  leg  is  a  waste-pipe.  The  water  of 
the  cistern  stands  84  feet  above  the  well.  There  is  an  air  chamber  on  each  pipe 
main. 

At  night  the  engine  pumps  into,  and  fills  the  Claremont  Square  reservoir, 
which  stands  50  feet  above  the  pump  well. 

This  station  (New  River  Head)  has  an  elevation  of  85  feet  above  the 
Thames,  and  the  lowest  portion  of  the  district  might  be  to  some  extent  supplied 
from  it  by  gravity.  I  could  not  learn  whether  this  was  the  case. 

From  the  capacity  of  the  pumping  engines  alone,  I  judge  that  the  whole 
delivery  from  this  station  may  average  (1866)  5k  million  gallons  per  diem,  or 
thereabout. 

The  whole  delivery  of  the  Works  of  the  New  River  Company  averaged 
nearly,  in  I860,  23  million  gallons  daily,  including  the  unfiltered  water  deliv- 
ered into  the  city  for  watering  the  streets. 

The  delivery  to  consumers,  with  the  exception  after  mentioned,  is  inter- 
mittent ;  and  every  house,  therefore,  has  a  cistern,  or  water  butt,  or  in  some 
other  way  holds  in  reserve  water  enough  to  meet  the  hours  when  the  supply  is 
interrupted.  There  are  1200  houses  which  receive  from  the  mains  what  is 
called  in  London  a  constant  supply,  but  the  supply-pipe  is  throttled  by  a  but- 
ton, having  in  it  a  small  hole  of  from  iV  to  I  inch  diameter,  according  to 
circumstances,  rendering  a  cistern  necessary  in  this  case  as  much  as  in  the  other. 
This  contrivance  limits  the  amount  of  water  delivered,  and  prevents  waste  ;  but 
it  also  neutralizes  the  advantages  aimed  at  by  a  constant  supply. 

Mr.  J.  Muir  is  the  Engineer  to  this  Company. 


EAST   LONDON   WATER  WORKS.  73 


EAST  LONDON  WATER  WORKS. 


The  East  London  Water  Works  Company  derives  its  supply  of  water  from 
the  lower  section  of  the  river  Lea,  by  means  of  a  canal  or  feeder  constructed 
for  that  purpose,  tapping  the  river  Lea  a  short  distance  above  Tottenham  Mills, 
at  a  point  4h  miles  above  Old  Ford. 

The  feeder  conducts  the  water  into  large  settling  reservoirs  at  Waltham, 
Stowe.  The  water,  after  passing  through  these,  is  conveyed  by  an  open  canal 
to  filter  beds  situated  at  Lea  Bridge.  Here  the  water,  after  undergoing  filtra- 
tion, is  conveyed  by  a  48-inch  pipe  main  to  the  pumping  engines  at  Old  Ford. 

The  average  delivery  from  these  works  was  stated  by  the  Engineer  to  be 
about  130  millions  weekly  to  89,000  tenements,  or  about  20  million  gallons 
daily.  There  are  no  high  service  reservoirs  connected  with  these  works.  The 
storage  of  water  is  large,  but  it  is  held  in  open  reservoirs  on  the  line  and  level 
of  the  feeder  aforesaid,  and  outside  of  the  parliamentary  limits. 

The  Lea  rises  in  Bedfordshire.  The  average  daily  flow  of  the  river  is  given 
as  equal  to  90  million  imperial  gallons,  but  the  minimum  flow  in  very  dry 
seasons,  judging  from  the  records  of  the  East  London  Water  Company,  does 
not  exceed  55  million  gallons. 

The  New  River  Company  is  entitled  to  take  22 \  million  gallons  daily,  and 
the  East  London  Water  Company  22 3  million  gallons  daily  ;  the  surplus  is  used 
by  the  River  Lea  Navigation  Company,  or  runs  to  waste  ;  but  the  two  Water 
Companies  are  authorized  to  take  and  deliver  as  much  more  as  can  be  obtained 
by  the  construction  of  storage  reservoirs  in  the  valley  of  the  Lea,  for  the  collec- 
tion of  its  flood  waters,  so  far  as  this  can  be  done  without  impairing  the  rights 
of  the  Navigation  Companies,  or  of  the  few  mill  privileges  existing  on  this 
stream. 

By  means  of  such  reservoirs  the  Engineers  estimate  that  the  supply  of  each 
Company  from  the  Lea  could  be  increased  by  eight  to  ten  million  gallons 
daily. 

This  system  of  storage  reservoirs  would  be  undertaken  jointly  by  the  two 
Companies. 

In  point  of  fact,  the  East  London  Company  possesses  now  storage  reservoirs 
at  Waltham  Stowe,  constructed  since  1864,  and  capable  of  adding  at  the  rate  of 


74  EAST   LONDON    WATER   WORKS. 

three  million  gallons  daily,  to  its  summer  average,  from  the  Lea  ;  but  these  reser- 
voirs collect  only  a  portion  of  the  flood  waters  of  the  lower  part  of  the  Lea. 
At  this  date,  as  elsewhere  stated,  the  New  River  Company  draws  eighteen 
million  gallons  of  its  supply  from  the  river  Lea,  the  balance  being  obtained 
from  wells  and  springs.  The  East  London  Water  Company  is  dependent  on  the 
Lea  for  its  entire  supply,  which  at  this  date  equals  an  average  of  20,  million 
gallons  daily.  But  during  the  lowest  stages  of  the  river  in  the  summers  of 
1863  and  1864,  the  daily  flow  for  some  weeks  did  not  exceed  17|  million 
gallons,  at  the  point  where  the  East  River  Company  taps  the  Lea,  and  during 
some  days  of  1864  it  was  as  low  as  15  millions.  The  Company  was  then  re- 
quiring an  average  of  18  to  19  million  gallons,  to  meet  the  current  consumption. 
This  condition  of  things  led  to  the  construction  of  the  reservoirs  referred  to,  as 
the  most  convenient  as  well  as  the  most  economical  mode  of  increasing  their 
supplies. 

The  water  of  the  river,  in  its  summer  or  low  water  stage,  is  but  slightly  dis- 
colored ;  but  after  rains  and  in  floods,  its  waters  being  gathered  from  a  rich  and 
well-settled  agricultural  country,  it  becomes  turbid,  and  carries  a  good  deal  of 
sediment.  For  many  years  the  waters  were  delivered  to  the  Londoners,  by  the 
two  Companies,  in  their  natural  state,  no  attempt  being  made  to  separate  either 
the  sedimentary  or  the  organic  impurities.  Parliament  at  length  interfered,  in 
1854,  to  protect  the  inhabitants,  and  required  the  filtration  of  all  waters 
intended  for  domestic  use.  The  means  taken  for  this  end  are  very  simple,  and 
have  proved  entirely  efficient. 

At  Waltham  Stowe  station,  there  are  now  three  settling  reservoirs  in  use, 
and  one  under  construction.  The  water  area  of  the  three  amounts  to  75  acres, 
and  when  the  fourth  is  completed  it  will  amount  to  115  acres.  The  annexed 
sketch  (Fig.  2,  Plate  XL),  which  is  not  to  scale,  will  explain  their  relative 
positions.  They  serve  the  purpose  of  storage  as  well  as  of  settling  reservoirs, 
and  may  be  said  to  be  about  as  important  for  the  one  purpose  as  the  other. 

Before  these  reservoirs  were  constructed,  the  feeder  itself,  some  six  miles  in 
length,  afforded  the  only  opportunity  between  the*iver  and  the  filter  beds,  for 
the  deposition  of  that  excess  of  sediment  which  occurs  in  times  of  flood  ;  the 
water  must  have  reached  the  filter  beds  then,  at  times,  in  a  very  turbid  state, 
causing  the  interruptions  to  be  proportionally  frequent  for  cleansing  them,  and 
largely  increasing  the  cost  of  that  process. 

The  reservoirs  are  so  arranged  as  to  admit  of  the  water  being  retained  in 
either  pair  at  rest  for  a  limited  time,  a  course  that  might  be  necessary  when 
the  river  was  in  flood  and  its  water  very  turbid.  Ordinarily,  it  is  sufficient  to 
pass  the  water  through  the  reservoirs,  causing  it  to  divide  and  flow — one-half 
through  No.  1  to  No.  2,  and  one-half  through  No.  4  and  No.  3  to  No.  2. 


EAST   LONDON   WATER   WORKS.  75 

In  this  way  the  water  flows  slowly  through  1^  miles  in  length  of  reservoirs, 
where  it  deposits  the  larger  portion  of  any  matters  held  in  suspension,  and 
passes  to  the  niters  unusually  well  prepared,  to  be  perfected  economically  by 
that  process. 

The  reservoirs  hold  from  10  to  20  feet  in  depth  of  water,  but  not  more  than 
seven  feet  of  this  water  can  be  drawn  off,  the  remainder  being  below  the  level 
of  the  canal  which  conveys  the  water  to  the  filter  beds.  The  reservoirs  are  not 
expected  to  be  cleaned  out  except  at  long  intervals.  They  are  all  artficial. 
The  bank  slopes  (3  to  1)  are  not  paved,  but  covered  with  coarse  shingle. 
In  the  centre  of  each  bank  there  is  a  puddle  wall  of  clay  six  feet  thick  at  top. 
The  Engineer  gives  the  capacity  of  the  three  reservoirs  as  equal  to  220 
million  gallons,  which  will  be  increased  to  500  million  gallons  when  the  con- 
templated additions  are  completed. 

There  is  an  engine-house  at  this  station,  and  a  pumping  engine  of  100- 
horse  power  in  it,  which  is  not,  however,  in  use. 

The  head  of  the  canal  which  conveys  the  water  from  the  reservoirs  after 
settlement,  is  situated  about  6  feet  below  the  level  of  the  feeder,  which  delivers 
the  Lea  water  into  the  reservoirs.  The  length  of  this  canal  is  about  liz  miles. 

LEA  BKIDGKE. 

The  canal  above  mentioned  terminates  at  the  Lea  Bridge  Works. 

At  this  station  there  are  two  sets  of  filter  beds,  one  on  the  left  bank  of  the 
river  Lea  and  one  on  the  right  bank. 

The  accompanying  sketch  (Plate  XI.)  shows  their  forms  and  positions.  On 
the  right  bank  there  are  seven  filter  beds  grouped  round  a  central  well,  into 
which  the  filtered  water  is  delivered  ;  these  are  marked^?,  p,  p,  p,  p,  p,  and^>, 
on  the  sketch. 

On  the  left  bank  of  the  Lea  there  are  six  filter  beds,  grouped  also  round  a 
central  well  ;  they  are  marked  q,  q,  q,  q,  q,  q. 

The  filter  beds  were  all  covered,  at  the  time  of  my  visit,  with  from  4  to  5 
feet  of  water,  except  one,  which  was  bare,  undergoing  the  process  of  cleansing. 

The  materials  of  the  filters  are  sand  and  gravel  4^  feet  deep ;  the  depth  of 
fine  sand  varying  from  18  to  30  inches,  according  to  the  time  which  has  inter- 
vened since  the  last  renewing.  The  gravel  is  screened  and  arranged  with  the 
largest  size  at  the  bottom.  The  bottom  is  of  concrete,  upon  which  are  laid  the 
drains  and  earthenware  pipes,  which  collect  the  filtered  water  and  carry  it  to 
the  central  well.  I  was  not  able  to  get  the  particular  size  and  arrangement 
of  these  pipes  in  this  case,  but  they  are  of  the  same  general  character  as 
those  used  at  the  other  works. 


76  EAST   LONDON    WATEE   WORKS. 

In  the  worst  state  of  the  river  a  filter  bed  is  cleaned  once  a  week,  but 
usually  it  suffices  to  clean  them  once  in  three  to  four  weeks.  The  Engineer 
informed  me  that  the  aggregate  filtering  area  cleaned  off  during  the  year 
averaged  160  acres.  This  is  equal  to  3.08  acres  cleaned  off  per  week. 

The  entire  sand  areas  of  the  filters  amount  to  12  acres,  which  would  give 
an  average  of  three  filter  beds  cleaned  each  week,  which  would  again  give  an 
average  for  each  filter  bed  of  a  cleaning  off  every  four  weeks.  About  half  an 
inch  of  sand  is  taken  off  in  the  process  of  cleansing.  The  foul  sand  is  washed 
and  used  over  again.  The  sand  is  not  replaced  upon  each  bed  oftener  than 
once  in  from  6  to  8  months. 

These  filter  beds  are  not  bounded  by  vertical  walls,  but  by  steep  slope- 
walls,  paved  with  brick.  The  air  pipes  come  to  the  surface  at  the  top  of 
the  slope. 

In  the  filter  bed,  which  was  bare,  there  were  three  pipes  visible  at  the  foot 
of  the  slope-wall  of  one  of  the  sides,  for  refilling  and  supplying  it  with  water. 
Each  of  these  pipes  delivered  its  water  into  a  small  semicircular  basin,  the 
walls  of  which  were  flush  with  the  surface  of  the  sand.  In  commencing  the 
refilling,  the  water  overflows  from  these  basins  slowly  upon  the  filter  bed. 

There  being  12  acres  of  filtering  area  here,  I  will  suppose  10  acres  of  it  to 
be  always  available  for  service.  The  water  supplied  averages  20  millions  per 
diem,  but  of  this  we  may  consider  15  millions  as  passing  through  the  filters 
during  the  12  hours  of  day,  the  filtered  water  reservoir  at  Old  Ford  not  being 
large  enough  to  equalize  the  rate  of  filtration  through  the  24  hours.  This  gives 
a  rate  during  the  day  of  about  70  gallons  per  square  foot.  With  all  the 
filter  beds  in  service,  the  rate  would  be  57  gallons  per  square  foot  per  diem. 

The  height  of  the  water  in  the  central  well  which  receives  the  filtered 
water,  as  compared  with  its  height  or  level  on  the  filter  beds,  shows  the  head 
required  to  produce  the  flow  through  the  filtering  material.  This  head  will 
vary  with  the  rate  of  that  flow,  the  extent  of  the  filtering  area  in  use,  and 
the  condition  of  the  sand  surface  (whether  it  be  recently  cleaned  or  nearly 
closed). 

The  well  belonging  to  the  set  of  filters  on  the  left  bank  of  the  Lea,  stood  at 
the  time  of  my  visit  3  feet  9  inches  below  the  level  of  the  water  upon  the  cor- 
responding filter  beds. 

Although  the  mode  of  filtration  adopted  on  the  London  works  was  origi- 
nally prepared  with  a  view  simply  of  depriving  the  river  water  of  the  sediment 
which  discolors  it  after  heavy  rains,  it  is  now  conceded  that  the  process  of  filtra- 
tion is  quite  as  desirable  in  summer,  to  deprive  such  water  of  the  floating 
vegetable  fibres  and  certain  animalcules  which  it  carries  in  suspension. 

During  certain  of  the  summer  months,  this  intercepted  matter  rapidly 
gums  up  the  surface  of  the  filter  beds  and  induces  vegetation  there.  At  these 


EAST   LONDON    WATER   WORKS.  77 

seasons  of  the  year  the  filter  beds  require  to  be  cleaned  off,  in  consequence  of 
this  coating  of  organic  matters,  about  as  frequently  as  when  the  river  is  in  flood. 

In  these  filter  beds,  for  instance  (as  related  by  Mr.  Maine,  one  of  the 
Company's  Managers)  during  the  month  of  July  of  every  year,  the  slimy 
matter  very  rapidly  deposits  upon  the  sand,  interrupting  the  filtration.  In  the 
month  of  August  this  slimy  matter  vegetates,  producing  green  confervoid  fibres, 
and  spreading  itself  like  a  green  carpet  over  the  surface  of  the  sand.  Doubt- 
less, the  other  London  Companies  could  testify  to  the  same  kind  of  experience. 

There  is  one  Cornish  beam  engine  (1866)  at  this  station. 

Steam  cylinder,  100  inches  diameter  ;  stroke  11  feet. 
Plunger,  50     "  "  "     11     " 

The  engine  was  at  work,  making  7  to  8  strokes  per  minute,  and  deliver- 
ing, I  was  told,  150  cubic  feet  per  stroke.  It  works  through  a  single-legged 
stand-pipe  directly  into  the  city  main.  There  is  also  an  air  chamber  on  the 
main.  It  has  a  battery  of  eight  boilers  ;  six  at  work,  two  at  rest.  Diameter  of 
boiler  5  feet  9  inches  each,  by  30  feet  in  length.  The  flue  3  feet  6  inches 
diameter.  Chimney  148  feet  high.  The  engine  has  been  working  since  1854 
day  and  night.  During  this  period  it  has  had  no  repairs  other  than  such  light 
work  as  could  be  done  at  the  smithy  on  the  premises. 

Although  this  engine  frequently  makes  10,000  strokes  in  24  hours,  yet 
the  ordinary  week's  work,  I  was  informed  by  the  Engineer,  seldom  exceeds  62 
to  64  million  imperial  gallons  for  seven  days.  Its  work,  therefore,  averages  9 
million  gallons  per  diem  at  present.  The  night  service  of  the  district  is  per- 
formed by  this  engine  alone,  the  engines  at  Old  Ford  being  then  at  rest.  Since 
my  visit  to  Lea  Bridge  in  1866,  two  new  engines  have  been  erected  there,  each 
with  a  steam  cylinder  of  84  inches  ;  the  other  particulars  of  these  I  am  not 
able  to  give. 

The  100-inch  engine  above  mentioned  seemed  to  be,  on  the  whole, 
the  most  satisfactory  specimen  of  the  Cornish  pumping  engine  to  be  seen  in 
London. 

The  cost  of  such  an  engine  now  (1866),  I  was  informed,  would  probably  be 
about  £15,000,  complete  in  all  respects. 

There  are  two  small  water-wheels  at  this  place  whose  pumps  work  into  the 
local  service  pipes. 

OLD   FOED. 

The  48-inch  pipe  main  already  mentioned,  which  conveys  the  filtered  water 
from  the  filtering  works  to  the  Old  Ford  Works,  is  two  miles  in  length. 

10 


78  EAST  LONDON  WATER  WORKS. 

At  Old  Ford,  it  delivers  the  water  into  a  covered  clear  water  basin.  This 
basin,  or  low  storage  reservoir  for  filtered  water,  has  an  area  of  2s  acres,  with 
a  depth  of  water  when  full  of  12  feet.  I  calculate  it  to  hold  about  seven  mil- 
lion gallons  of  water.  The  filtered  water  is  running  into  this  basin  night  and 
day. 

The  pumping  engines  at  Old  Ford  draw  down  this  basin  during  the  day 
hours  when  they  are  at  work,  and  at  night,  when  they  are  not  at  work,  the  un- 
interrupted flow  from  the  filters  fills  it.  The  basin,  however,  is  not  large 
enough  to  make  the  rate  of  flow,  and  therefore  of  filtration,  uniform  during  the 
day  and  night  hours.  From  this  basin  the  water  has  free  access  to  the  different 
pumping  engines  by  a  conduit  with  suitable  sluices. 

The  48-inch  main  has  a  lateral  connection  with  the  wells  of  the  pumping 
engines,  independent  of  the  covered  basin  referred  to,  in  order  that,  when  that 
basin  requires  repairs  or  cleansing,  the  flow  of  filtered  water  to  the  pumps  may 
not  be  interrupted.  At  this  station  there  are  also  two  open  reservoirs,  kept 
full  of  unfiltered  water  from  the  Company's  canal.  They  are  not,  however,  in 
use,  although  they  have  been  permitted  to  remain,  as  a  measure  of  precaution 
against  unforeseen  emergencies. 

There  are  four  single-acting  beam  engines  here,  of  the  Cornish  variety. 
The  general  characteristics  are  as  follows  : 

No.  I.—'1  Hercules." 

Steam  cylinder,  85  inches  diameter  ;  stroke,  10  feet,  cutting  off  at  one-third. 
SOlbs.  steam  shown  by  gauge  in  engine-room,  making  8  to  9  strokes  per 
minute.  Double  beam — length,  29  feet  c.  c. — depth  at  centre,  6  feet. 

Plunger,  43-inch  diameter  ;    stroke,  9  feet. 

One  stand-pipe  to  the  four  engines,  with  a  single  leg  135  feet  in  height 
and  5  feet  diameter. 

For  suction  valves,  two  double-beat  valves. 

Delivery  valve,  one  double-beat  valve. 

The  outer  beat  is  55  inches  diameter  ;  the  inner  beat  43  inches.  The  beats 
are  level,  and  metal  to  metal. 

The  engine  works  into  the  City  main,  not  through  the  stand-pipe,  but  the 
main  is  connected  with  the  stand-pipe. 

The  engine  has  a  battery  of  4  Cornish  boilers,  three  of  which  were  in  use, 
the  fourth  in  reserve. 

Diameter  of  shell,  69  inches  ;  length,  30  feet. 

Length  of  fire-place,  6  feet. 

There  is  but  one  chimney  here  for  the  four  batteries  of  the  four  engines, 
height  175  feet. 


EAST   LONDON    WATER    WORKS.  79 


No.  2.— *' Cornish." 

Steam  cylinder,  80  inches ;  stroke,  10  feet,  making  eight  strokes  per 
minute. 

Plunger,  41  inches  diameter  ;  stroke,  9  feet. 

This  engine  works  directly  into  the  stand-pipe.  The  gauge  in  the  engine- 
room  showed  a  pressure  of  95  feet. 

Suction  valve,  a  double-beat  valve. 

Delivery  valve,  the  game. 

Four  boilers,  carrying  35  Ibs,  steam  ;  shell  of  boiler,  69  inches ;  length,  30 
feet.  Diameter  of  flue,  42  inches. 

No.  S.—  "Ajax." 

Steam  cylinder,  72  inches  ;  stroke,  10  feet,  making  8  to  nine  strokes  per 
minute. 

Double  beam,  cast-iron;  length,  30  feet  c.  c.  ;  depth  at  centre,  6  feet.  The 
flitches  8  inches  apart. 

Plunger,  36  inches  diameter  ;  stroke,  10  feet. 

The  suction  valve  is  a  double-beat  valve. 

The  delivery  valve  is  one  of  Austin's  patent  cone  valves,  with  horizontal 
india-rubber  rings.  This  valve  is  considered  good  for  delivery  valves,  but  the 
other  valve  is  preferred  here  for  suction  valves. 

The  delivery  main  is  connected  with  the  stand-pipe.  The  gauge  in  the 
engine-room  showed  a  pressure  of  85  feet. 

Four  Cornish  boilers — shell,  69  inches  ;  length,  30  feet ;  flue,  42  inches. 

No.  4.— "WicJcsteed,"  184:7. 

Steam  cylinder,  90  inches  ;  stroke,  11  feet  ;  30  Ibs.  steam  in  engine-room. 

Cutting  off  at  one-fourth,  8j  strokes  per  minute. 

Double  beam,  cast-iron  ;  length,  36  feet  c.  c.;  depth  at  centre,  7feet  6  inches  ; 
weight,  35  tons  ;  gudgeon,  16-inch  diameter. 

Plunger,  44  inches  diameter  ;  stroke,  11  feet ;  40-inch  main  from  engine 
to  stand-pipe. 

Suction  valve,  double  beat. 

Delivery  valve,  double  beat. 

The  pump  was  stated  to  be  delivering  at  the  rate  of  5,700  imperial  gallons 
per  minute. 

The  gauge  in  the  engine-room  showed  a  varying  pressure  of  84  to  88  feet 
with  each  stroke. 


80  EAST   LONDON   WATES   WORKS. 

This  engine,  like  the  other,  has  a  battery  of  four  Cornish  boilers,  of  same 
dimensions  each  as  those  already  given.  The  steam-pipe  from  the  boilers  was 
of  15  inches  diameter,  and  cased.  All  of  the  four  engines  have  steam 
jackets.  In  this  engine  and  in  the  Hercules  there  is  also  a  steam  cover. 
The  actual  stroke  made  is  usually  from  2  to  4  inches  below  the  lengths 
here  given. 

These  four  engines  were  all  at  work  (1866).  They  are  all  kept  at  work 
during  the  day  and  all  at  rest  during  the  night.  I  judged  them,  from  their 
dimensions,  to  be  delivering  about  12  million  gallons  in  12  hours. 

(On  my  visit  to  the  works,  on  4th  August,  1868,  there  were  but  three  en- 
gines at  work,  No.  3  being  at  rest  ;  but  the  river  supply  had  been  deficient  that 
season,  and  the  Company  found  it  difficult  to  meet  besides,  the  increased 
consumption  produced  by  the  great  heat  of  the  summer.  On  this  day  the 
water  in  the  adjoining  covered  reservoirs  stood  5  feet  below  its  ordinary  level.) 

All  the  engines  work  directly  into  the  mains,  either  through  or  connected 
with  the  single-legged  stand-pipe,  against  not  exceeding  a  hundred  feet  of  head. 
Each  engine  is  connected  with  an  air  chamber.  Of  the  four  boilers  connected 
with  each  engine,  three  are  in  use  in  each  case  and  one  in  reserve. 

The  engines  were  making  8  to  9  strokes  per  minute. 

There  are  two  small  rotative  beam  engines  at  this  station,  serving  generally 
a  special  high  corner  of  the  district. 

The  East  Twin  and  the  West  Twin. 

These  engines  are  sixty  years  old.  The  East  Twin  working,  the  other  at 
rest. 

Steam  cylinder,  36  inches  ;  stroke,  8  feet. 

Crank  and  fly-wheel  inside  of  the  pump. 

Crank,  2  <z  feet  c.  c.;  fly-wheel,  13  feet  diameter. 

Two  lifting-pumps.  The  outer  pump,  18  inches  diameter  ;  8  feet  stroke. 
The  inner  pump,  15  inches  diameter  ;  6  feet  stroke.  The  outer  pump  was  dis- 
connected. The  inner  pump  was  working  into  the  high  service,  against  a 
pressure  of  from  140  to  150  feet  head. 

Each  engine  has  an  air  chamber  on  the  line  of  main,  inside  of  the  house. 
There  were  two  Cornish  boilers  for  these  engines  ;  one  only  at  work. 

The  liberal  scale  on  which  the  settling  reservoirs  and  filtering  works  of  the 
East  London  "Water  Works  are  constructed  must  produce  very  satisfactory 
results,  both  as  regards  the  sufficiency  and  the  economy  of  the  process.  The 
pumping  machinery  here  is  more  than  usually  uniform,  and  excellent  of  its 
class. 


EAST  LONDON  WATER  WORKS.  81 

In  1849,  the  Company  is  reported  to  have  delivered  into  its  district  a  daily 

average  of 830,000  imperial  gallons. 

In  1855 1,600,000 

In  1866,  the  delivery  averaged 20,000,000         " 

Mr.  Charles  Graves  is  the  Engineer  of  these  works.  They  were  at  one  time 
under  the  direction  of  Mr.  Wicksteed,  and  it  was  here  that  what  is  now  called 
the  Cornish  form  of  pumping-engine  was  first  applied  by  Mr.  W.  to  city  water 
works. 


82  LEICESTER   WATER   WORKS, 


LEICESTER  WATER    WORKS,  June,    18CG. 

The  city  of  Leicester  is  situated  on  the  small  river  Soar,  a  tributary  of  the 
Prent.  The  city  is  supplied  with  water  from  Markfield  brook,  a  small  upland 
brook  which  runs  into  the  Soar  below  Leicester.  A  reservoir  has  been  con- 
structed on  the  valley  of  this  brook,  near  the  village  of  Thornton,  about  8  miles 
west  from  Leicester.  The  sources  of  the  brook  rise  in  a  sandstone  and  shale 
district  to  the  north  of  the  reservoir.  The  water  collected  has  about  9  degrees 
of  hardness,  by  Clark's  scale.  Before  the  construction  of  these  works  the  city 
was  entirely  supplied  from  wells,  many  of  which  are  used  now,  although  the 
well  water  is  very  much  harder  than  the  Thornton  water. 

The  population  of  Leicester  was  stated  to  number  about  75,000,  of  which 
50,000  were  supposed  to  be  supplied  by  the  Water  Company. 

The  works  consist  of  the  reservoir  above  mentioned,  four  filter  beds  imme- 
diately below  the  reservoir  embankment,  and  a  reservoir  near  the  city  which 
receives  and  stores  the  water  after  nitration. 

The  reservoir  has  a  water  surface,  when  full,  of  78  acres.  It  must  have  a 
capacity,  I  judge,  of  100  days'  supply,  and  yet,  during  two  exceptionally  dry 
years,  its  reserve  of  water  had  proved,  as  was  stated  to  me,  barely  sufficient, 
and  the  Company  have  now  under  consideration  the  construction  of  a  second 
reservoir. 

The  filter  beds  are  situated  immediately  to  the  south  of  the  reservoir  em- 
bankment, low  enough  to  command  the  entire  water  of  the  reservoir.  From 
the  reservoir  there  are  two  pipes  to  convey  its  water  to  the  filter  beds.  One 
of  these  is  a  siphon  pipe  of  12  inches  diameter.  This  is  used  until  the  water 
gets  below  the  siphon  mouth.  The  other  is  an  18-inch  pipe,  laid  through  the 
bottom  of  the  embankment,  which  commands  that  portion  of  the  water  lying 
below  the  reach  of  the  siphon. 

The  forms  of  the  four  filter  beds  are  shown  on  the  accompanying  sketch 
(Plate  XII.),  where  they  are  marked  a1,  a2,  a3,  a4.  The  central  well  (b),  66  feet 
in  diameter,  receives  the  filtered  water  from  an  overflow  pipe  in  its  centre. 
Each  filter  measures  100  feet  by  66  feet,  giving  to  each  6,600  square  feet  of 
sand  surface.  The  walls  of  these  filters  are  built  of  stone,  and  vertical.  They 
are  backed  with  clay  puddle.  The  bottom  is  also  puddled  with  clay,  over 
which  paving  slabs  are  laid,  and  upon  these  a  brick  paving. 

The  materials  of  the  filters  are  sand,  gravel,  and  broken  stone,  to  the  depth 
of  seven  feet."  The  sand,  originally  36  inches,  is  now  reduced  to  24  inches,  it 


LEICESTER   WATER   WORKS.  83 

was  stated,  upon  two  of  the  filter  beds  ;  on  the  other  two  it  is  36  inches  now, 
having  been  replaced,  I  presume,  to  that  depth.  The  sand  is  coarser  than  any 
that  I  have  seen  used  for  this  purpose.  Deducting  three  feet  of  sand,  there 
remains  4  feet  of  gravel  and  broken  stone.  A  central  brick  drain,  with  clay 
pipes  running  from  either  side  of  it,  collects  the  filtered  water  and  delivers  it  into 
the  clear  water  well  (b).  These  pipes  (6  inches  in  diameter)  are  not  perforated. 
The  water  enters  at  the  joints,  which  are  kept  apart  about  an  inch,  or  as  much 
as  the  size  of  the  broken  stone  will  admit. 

A  10-inch  iron  pipe  at  the  corner  of  each  filter  bed  is  connected  with  the 
reservoir  pipe,  and  delivers  the  required  amount  of  water  upon  the  bed.  The 
mouth  of  this  pipe  is  surrounded  with  cobble  stone,  upon  which  the  water  over- 
flows slowly  when  the  sand  bed  is  bare  and  until  there  is  a  sufficient  depth  of 
water  to  protect  the  sand.  There  is  a  waste-pipe  at  another  corner,  standing 
24  inches  above  the  full  water  line,  and  the  water  in  these  filters  is  limited  by 
the  height  of  this  pipe.  To-day  there  were  but  18  inches  of  water  upon  the 
beds.  The  filters  are  cleansed  off  from  once  in  six  days  to  once  in  three  weeks, 
according  to  the  character  of  the  water.  I  was  told  that  when  the  brooks  were 
flooded  and  the  reservoir  at  the  same  time  rather  low,  the  water  became  quite 
turbid.  At  the  time  of  my  visit  the  reservoir  water  was  comparatively  clear, 
but  seen  in  a  tumbler,  there  were  numerous  small  animalcules  visible,  moving 
about  briskly.  The  water  after  filtration  was  quite  bright  and  entirely  free 
from  any  appearance  of  this  kind.  These  small  living  organisms  occur,  we 
presume,  in  all  waters  at  certain  seasons  of  the  year.  There  they  are  visible 
twice  a  year  for  a  short  period.  The  only  use  of  the  filters  for  a  large  portion 
of  the  year  is  to  intercept  and  remove  all  organic  matters,  vegetable  or  animal. 

The  sand  removed  in  the  cleansing  process  is  washed  and  laid  aside,  to  be 
replaced  at  intervals. 

Two  of  the  filters  were  in  use  at  the  time  of  my  visit,  the  other  two  being 
dry  and  ready  for  use.  When  the  reservoir  is  made  turbid  after  heavy  rains, 
three  are  used,  and  at  the  worst  the  whole  four. 

The  average  delivery  of  water  by  this  Company  to  the  city  of  Leicester  is 
1,200,000  imperial  gallons  (192,551  cubic  feet),  equal  to  1,440,380  U.  S.  gallons 
per  diem,  as  given  me  by  the  Superintending  Engineer. 

With  two  filter  beds  in  use  (sand  area  6,600X2=13,200  square  feet),  the 
rate  of  filtration  is  about  109  U.  S.  gallons  per  square  foot  per  diem.  This 
was  the  rate  at  this  time.  When  the  water  contains  a  perceptible  portion  of 
sediment,  the  rate  with  three  filters  averages  82  U.  S.  gallons,  and  with  the 
four,  54<z  U.  S.  gallons  per  square  foot  per  diem. 

An  18-inch  pipe,  whose  mouth  is  covered  by  a  grating,  enters  the  clear 
water  well  b,  and  conveys  the  filtered  water  thence  to  the  New  Parks  reservoir, 
situated  about  2 \  miles  southwest  of  the  city.  The  length  of  this  pipe  was 


84  LEICESTEE   WATER   WORKS. 

stated  to  be  about  7  miles.  The  clear  water  reservoir  above  mentioned  stands 
1 30  feet  above  the  Hay  Market,  Leicester,  and  commands  the  entire  city.  This 
is  a  covered  reservoir,  with  a  capacity,  Mr.  Bevins  stated,  of  two  days'  supply, 
that  is.  of  about  2 2  million  gallons.  This  reservoir  is  sufficiently  large  to 
admit  of  (with  some  regulation)  the  rate  of  nitration  being  maintained  uniform 
night  and  day. 

These  works  were  constructed  after  the  designs  of  Mr.  Hawksley.     Mr. 
Bevins  is  the  Superintending  Engineer. 


or 

OF  CWB. 
BERKELEY.  CALIFORNIA 

YORK   WATER   WORKS.  85 


YORK  WATER  WORKS, 


YOEK,  3rd  September,  1866. 

The  city  of  York  lies  on  the  river  Ouse,  which  delivers  its  waters  into  the 
estuary  of  the  Humber. 

The  water  for  the  supply  of  the  city  is  derived  from  the  Ouse  at  a  point 
near  Acombs'  Landing,  about  two  miles  above  the  city. 

The  sources  of  the  Ouse  lie  on  the  high  lands  dividing  the  North  Riding 
of  Yorkshire  from  Westmoreland. 

The  prevailing  rocks  there  are  the  upper  limestone  shales  and  the  millstone 
grit. 

Whenever  heavy  rains  occur,  the  water  in  the- river  is  decidedly  turbid  at 
York.  It  was  so  at  the  date  of  my  visit  (September,  1866),  though  the  river 
then  was  but  four  feet  above  its  lowest  stage.  In  extreme  floods  it  rises  ten 
to  twelve  feet,  and  spreads  over  a  large  extent  of  meadow  lands. 

The  works  of  the  "  York  New  Water  Works  Company,"  situated  at 
Acombs'  Landing,  consist  of  an  engine-house  and  two  .pumping-engines,  two 
settling  basins,  three  filter  beds,  and  a  reservoir  for  the  filtered  water  placed 
upon  sufficiently  high  ground  to  command  the  city. 

The  two  pumping-engines  are  in  all  respects  alike.  They  are  of  the  Cor- 
nish form  of  single-acting  beam  engines. 

Each  engine  has  two  plunger  pumps,  one  of  which  is  used  for  lifting  the 
river  water  into  the  settling  basins  ;  and  the  other  for  lifting  the  filtered  water 
into  the  high  reservoirs,  whence  it  passes  to  the  city. 

The  two  pumps  are  not  worked  at  the  same  time,  one  of  them  being 
thrown  out  of  gear  when  the  other  is  in  use.  There  was  but  one  engine  at 
work  at  the  time  of  my  visit,  pumping  into  the  high  reservoir.  In  practice  one 
engine  pumps  the  filtered  water  through  the  24  hours,  except  10  to  15  minutes  ; 
and  the  other  pumps  the  river  water  for  9  to  10  hours  daily,  the  greater  size 
of  the  low-service  pump  enabling  it  to  do  its  work  in  so  much  less  time.  The 
engines  alternate  under  this  arrangement  from  month  to  month. 

The  general  dimensions  are  : 

Steam  cylinder,        36  inches  diameter  ;  8  ft.  4  inches  stroke. 
River  pump,  30      "  "  9  " 

Clear-water  pump,   20      "  "  6"    4      " 

11 


86  YORK   WATER   WORKS. 

The  engine  was  making  12?z  strokes  per  minute,  the  service  requiring  that 
rate,  but  10i  strokes  is  considered  its  best  working  rate. 

The  delivery  per  diem  was  stated  to  average  1,500,000  gallons  into  the 
high  reservoir.  For  the  last  week  of  August,  on  record,  it  was  10,800,000 
imperial  gallons,  which  was  equal  to  1,542,855  gallons  per  diem. 

The  water  in  the  high  reservoir  stands  110  feet  above  the  clear-water  pump 
well.  The  river-water  pump  has  a  lift  ordinarily  of  24  feet,  varying  with  the 
stage  of  the  river.  The  walking  beam  of  each  engine  carries  two  sliding  blocks 
of  cast-iron,  whose  position  is  adjusted  according  as  the  low  or  high  service 
pump  is  in  use.  The  river  water  is  carried  to  the  engines  by  a  21-inch  pipe, 
and  is  delivered  to  the  settling  basins  through  a  21-inch  pipe. 

The  pipe,  or  rising  main,  which  delivers  the  filtered  water  from  the  small 
pump  to  the  high  reservoir,  is  12  inches  diameter,  and  about  2,500  feet  in. 
length.  A  second  rising  main  of  21  inches  diameter  was  being  laid. 

The  accompanying  sketch  will  show  the  arrangement  of  the  settling  basins 
and  filter  beds.  (Plate  13.) 

The  two  settling  basins  are  intended  to  hold  2,500,000  gallons  each  when 
full.  After  being  filled  the  water  stands  usually  14  hours  in  each  settling  basin 
before  being  drawn  off  upon  the  filter  beds  ;  but  this  advantage  is  in  part  lost 
by  the  mode  of  drawing  off,  which  is  from  the  bottom.  The  original  arrange- 
ment had  in  view  the  drawing  off  the  water  from  the  surface,  where  it  is  always 
clearest ;  but  some  defects  in  its  working  led  the  attendants  to  use  the  other 
method.  The  settling  basins  are  each  cleared  out  once  a  year. 

A  12-inch  pipe  carries  the  water  from  the  settling  basins  along  the  head  of 
the  filter  beds.  From  this  pipe  a  9-inch  branch,  with  a  stopcock,  communicates 
with  each  bed — the  water  being  delivered  from  the  9-inch  pipe  upon  each  bed 
by  four  smaller  pipes  of  4-inch  diameter  each.  At  the  terminus  of  each  small 
pipe  a  wooden  trough,  perforated  with  holes,  receives  the  water  and  delivers  it 
upon  the  sand.  The  box  is  intended  to  break  the  flow  from  the  pipe,  and  defend 
the  sand-bed  from  being  rutted. 

The  sides  of  the  filters  are  pitched  with  a  rough  pitching  of  9-inch  stone, 
sloped  at  2  to  1,  resting  on  4  inches  of  concrete  and  grouted.  The  bottom  is 
puddled,  and  there  is  a  puddle  wall  in  each  dividing  bank,  and  around  the  outer 
boundaries. 

The  materials  of  each  filter  are  as  follows : 

Sand 30  inches. 

Fine  gravel 6     " 

Broken  stone  or  large  shingle,  screened 24     " 

60  inches. 


YORK   WATER   WORKS.  87 

A  layer  of  4  inches  of  concrete  intervenes  between  the  puddle  and  the 
shingle,  and  forms  the  base  of  the  Biter  bed.  Upon  this  surface  of  concrete  a 
central  dry-stone  drain  runs  lengthwise  of  each  bed,  into  which  6-inch  clay 
pipes,  laid  on  either  side  of  this  centre,  deliver  the  filtered  water.  This  drain  is 
carried  into  a  well-hole,  from  which  a  15-inch  pipe  carries  the  water  to  the 
clear-water  pump.  At  each  of  these  well-holes  a  sluice  enables  the  attendant 
to  regulate  the  action  of  each  filter  bed. 

These  filter  beds  are  overworked  at  present,  and  the  company  is  about 
constructing  a  fourth  filter  to  be  circular,  and  160  feet  in  diameter.  This  new 
filter,  if  the  side  walls  are  built  vertical,  as  was  stated,  will  possess  a  capacity 
of  filtration  about  equal  to  the  other  three.  When  a  filter  is  clean,  12  inches 
of  head  will  readily  pass  the  proper  amount  of  water  ;  but  as  they  become 
clogged  with  sediment,  3  feet  of  head  is  frequently  necessary.  In  these  filters 
the  three  feet,  as  I  gathered,  is  sometimes  exceeded,  showing  that  the  filter  beds 
are  allowed  to  become  very  foul  before  being  cleaned  off.  In  these  filters  the 
additional  head  is  given  by  adding  to  the  depth  of  water  over  the  filter  bed. 

One  of  the  filter  beds  was  being  cleansed  at  the  time  of  my  visit ;  the  other 
two  were  covered  with  water — the  one  having  four  feet  of  water  upon  it,  and 
the  other  five  feet. 

A  filter  is  cleaned  off  once  a  month,  and  the  Superintendent  informed  me 
that  the  cleansing  was  as  necessary  when  the  river  was  low,  and  comparatively 
clear,  as  when  it  was  high  and  turbid.  When  low  the  fine  vegetable  threads  and 
particles  carried  by  the  water  then,  being  intercepted  by  the  sand,  form  a  com- 
pact and  close  coating,  like  velvet,  as  he  described  it.  But  this  would  not  be 
so  sensibly  felt  if  the  filter  beds  were  cleaned  off  oftener.  When  the  filter  is 
cleansed  off,  the  sand,  which  has  always  packed  considerably,  is  loosened  by 
delving  it  with  spades  and  afterwards  smoothly  raking  it  over  before  the  water 
is  let  on.  I  was  informed  that  the  sand  became  discolored  for  9  inches  below 
the  surface  here — a  proof  apparently  of  the  undue  pressure  under  which  the 
water  is  passed  through  it,  according  as  the  filter  gets  foul ;  in  other  words,  of 
the  proper  time  for  cleansing  it  off  having  been  usually  passed.  The  sand  was 
fine  and  of  good  quality,  but  containing  many  black  particles  of  slate  or  shale. 

Each  of  the  filter  beds  has  a  sand  area  of  60  feet  by  120  feet,  or  7,200 
square  feet.  The  three  filters  have  a  joint  sand  area  of  21,600  square  feet.  The 
amount  of  water  used  daily  being  1,500,000  gallons,  the  rate  of  filtration  with 
the  three  filters  in  use  is  about  69£  imperial  gallons  per  square  foot  per  diem, 
and  with  but  two  in  use  it  is  at  the  rate  of  104  gallons  per  square  foot. 

The  clear-water  reservoir  is  situated  upon  a  piece  of  high  ground  within 
half  a  mile  of  the  works  above  described.  It  is  open,  and  consists  of  one 
apartment,  holding  12  feet  of  water,  and  having  a  capacity  of  about  three  mil- 
lion gallons.  It  stands  110  feet  above  the  filter  beds.  A  15-inch  pipe  main,  a 


88  YORK   WATER   WORKS. 

little  over  two  miles  in  length,  carries  the  filtered  water  from  this  reservoir  to 
the  city. 

To  meet  the  wants  of  a  small  district  of  the  city  too  high  to  be  commanded 
by  this  reservoir,  a  stand-pipe  has  been  erected  on  the  reservoir  ground,  whose 
bend  is  18  feet  above  the  full  water  of  the  reservoir.  For  a  certain  number  of 
hours  every  night  the  engine  pumps  over  this  stand-pipe.  During  these  hours 
the  15-inch  pipe  main  is  disconnected  from  the  reservoir,  and  also  from  the 
lower  part  of  the  city,  and  the  houses  on  the  high  ground  referred  _to  are 
enabled  to  fill  their  cisterns.  The  service  upon  the  city  is  constant  for  twelve 
hours.  To  meet  the  wants  of  the  other  twelve  the  houses  have  cisterns,  butts, 
or  vessels  of  some  kind  for  the  necessary  reserve  of  water. 

In  1851,  the  population  of  York  was  36,303  ;  in  1861,  40,377  ;  and  in 
1866,  it  is  supposed  to  be  43,000.  The  Water  Company,  however,  supplies 
certain  suburbs  outside  of  the  census  population,  raising  the  population  sup- 
plied by  its  waters  to  at  least  45,000.  This  gives  a  rate  of  delivery  per 
head  of  upwards  of  33  gallons.  This  rate  includes,  as  usual,  the  water  ap- 
plied to  all  other  purposes.  It  is  more  than  generally  obtains  in  England, 
and  is  an  unusually  liberal  supply  for  a  provincial  city. 

Mr.  John  Watson,  the  Secretary  of  the  Company,  furnished  me  very 
politely  with  the  requisite  facilities  and  information  to  understand  the  works, 
as  did  Mr.  Edward  Hastier,  the  Superintendent. 


LIVERPOOL    WATER   WORKS.  89 


LIVERPOOL  WATER  WORKS, 


LIVEHPOOL,  August,  18C6. 

The  city  of  Liverpool,  lying  upon  tide-water  on  the  right  bank  of  the 
Mersey,  is,  commercially  speaking,  the  most  important  city  of  Great  Britain. 

The  tonnage  of  this  port  exceeds  that  of  London. 

In  1861,  the  population,  by  the  census,  was  437,740  ;  at  this  date  it  is  sup- 
posed to  amount  to  500,000. 

Up  to  1857,  all  the  water  of  Liverpool  was  obtained  from  wells  sunk  in  the 
new  red  sandstone  strata  which  overlie  the  coal  beds  of  Lancashire. 

The  water  supplied  to  the  city  at  this  date  is  derived  in  part  from  these 
wells  and  in  part  from  the  new  works  at  Rivington.  The  portion  derived  from 
wells  was  stated  by  Mr.  Duncan,  the  Engineer,  in  1863,  to  average  6.63  million 
gallons  per  diem,  from  seven  wells.  At  present  the  amount  received  is  5.61 
million,  from  six  wells  ;  but  when  the  improvements  now  in  progress  at  two  of 
the  well  stations  are  completed,  the  amount  is  expected  to  be  increased  to  7.61 
millions  per  diem. 

The  increase  has  not  been  gained  by  sinking  new  wells,  but  by  deepening 
two  of  the  old  ones,  and  by  adding  to  the  pumping  power  there. 

The  water  from  the  wells  is  very  clear  and  exceedingly  palatable.  It  is 
delivered  into  the  same  pipes  and  reservoirs  as  the  Rivington  water,  which  is 
derived  from  surface  collections. 

There  are  seven  wells  or  pumping  stations,  and  12  pumping  engines.  The 
wells  are  from  130  to  250  feet  in  depth.  The  practicability  of  increasing  the 
well  supply  is  at  present  being  tested  by  boring  250  feet  below  the  present 
bottom  of  one  of  the  wells,  into  a  lower  series  of  sandstone. 

The  pumping  engines  are,  some  of  them,  single-acting  Cornish  engines, 
and  some  of  them  rotary  engines.  The  working  expense  of  the  first  have 
been  found,  by  Mr.  Duncan,  to  equal  17  shillings  per  million  imperial  gal- 
lons, per  100  feet  of  lift,  and  the  average  expenses  of  all  the  engines  to  be 
equal  to  39  shillings  per  million  imperial  gallons,  per  100  feet  of  lift. 

The  rotary  engines,  however,  are  mostly  old  engines.  We  know  that  there 
is  but  little  difference  in  the  fuel  economy  of  the  one  engine  over  the  other, 
when  the  rotary  engine  is  equally  perfect  in  its  workmanship,  in  its  ability  to 
use  steam  expansively,  and  in  its  boilers,  and  when  it  is  equally  faithfully 
tended. 


90 


LIVERPOOL    WATER    WORKS. 


The  delivery  of  water  by  the  Corporation  Works,  at  this  date  (August, 
1806),  was  stated  to  average  13,000,000  gallons  imperial  per  diem.  The 
amount  received  from  the  new  works  is  therefore  (13,561)  7.39  million  gallons 
per  diem,  at  present. 

The  population  of  the  city  of  Liverpool,  at  this  date,  has  already  been 
given  as  500,000,  but  the  Corporation  Water  Works  supply  as  well  the  town  of 
Prescott,  and  the  outskirts  between  Prescott  and  Liverpool,  comprising  on  the 
whole  a  population  of  about  600,000.  The  rate  per  head,  therefore,  averages 
but  little  above  20  gallons  per  diem,  a  rate  which  does  not  satisfy  the  growing 
wants  of  the  population. 

This  port  which,  as  regards  tonnage,  is  the  largest  and  most  important  in 
Great  Britain,  requires  for  its  shipping  alone,  and  for  the  purposes  of  its  docks, 
stores,  and  wharves,  a  large  amount  of  water.  The  supply  at  present  is  not 
constant  through  the  24  hours,  but  it  is  constant  for  12  hours  of  each  day. 
With  a  more  abundant  supply  this  system  would  be  changed  to  that  of  constant 
service  through  the  24  hours.  All  the  water  received  from  the  Pvivington 
Works  is  filtered.  The  water  from  the  wells  does  not  require  filtration. 

The  water  of  the  Rivington  Works  is  collected  from  the  high  grounds 
lying  between  Blackburn  and  Bolton,  in  Lancashire.  A  part  of  this  water-shed 
consists  of  cultivated  ground,  though  the  larger  portion  of  it  is  in  pasture.  The 
rock  formation  belongs  to^the  sandstones  and  shales  of  the  coal  measures,  and 
to  the  millstone  grit.  There  are  six  collecting  reservoirs,  five  of  which  serve  as 
well  for  compensation  reservoirs,  delivering  a  fixed  daily  quantum  of  water  to 
the  mill  properties  below,  in  compensation  for  the  water  taken  for  city  use.  The 
reservoirs  are  as  follows  : 


NAME  OF  RESEBVOIB. 

Water 
Area 

Capacity 
in 
Millions  of 
gallons. 

Height 
above 
Tide. 

Greatest 
Depth 
Full. 

• 

Acres. 

Feet. 

Feet. 

1.  Upper   Eoddlesworth, 

38. 

180. 

620. 

61. 

2.  Lower    Eoddlesworth, 
3.  Rake  Brooke,  

16.4 
13  8 

99. 
79.6 

550. 
550. 

78. 
78. 

4.  Anglezark,  

191  6 

1019  6 

470 

35. 

5.  Chorley        

10  2 

48  3 

430 

39 

6.  Rivington  in  2  divisions 

275. 

1841. 

428. 

40. 

545. 

3267.5 

The  filter  beds,  which  stand  382  feet  above  tide,  are  situated  in  the  valley 
of  the  Douglass  brook,  immediately  below  the  embankmentof  the  lower  Rivington 


LIVERPOOL    WATER   WORKS.  91 

reservoir.  These  reservoirs  are  not  all  situated  in  the  valley  of  the  same  stream. 
The  higher  ones  are  upon  brooks  which  are  tributaries  of  the  Derwent  river, 
and  the  lower  ones  upon  tributaries  of  the  Douglass  river,  both  rivers  delivering 
into  the  Rebble.  The  water  of  each  reservoir,  however,  is  carried  by  an  open 
cutting  into  the  reservoir  below  it,  with  the  exception  of  what  is  measured  off 
to  the  millers,  and  of  any  portion  that  may  run  to  waste  at  the  overflows.  The 
whole  of  the  available  water  of  all  the  reservoirs  becomes  thus  concentrated  upon 
the  lower  division  of  the  Rivington  reservoir.  These  works  were  designed  by 
Mr.  Hawksley,  and  constructed  from  his  plans.  The  drainage  area,  or  water- 
shed of  all  these  reservoirs  comprehends  10,000  acres.  The  water  due  to  the 
millers,  under  all  circumstances,  and  delivered  into  the  several  streams  for  their 
use,  amounts  in  all  to  8,300,000  imperial  gallons  per  diem. 

In  designing  the  works,  the  mean  rain  fall  of  the  district  (in  defect  of  pre- 
cise information)  was  taken  at  48  inches,  and  of  this  the  amount  collectable  was 
assumed  to  be  36  inches  (75  per  cent.),  of  which  12  inches  was  intended  to  be 
given  to  the  millers  for  compensation.  This  estimate  of  the  amount  available 
has  not  been  verified. 

In  1861,  1862,  and  1863,  a  considerable  portion  of  water  was  wasted  over 
the  waste  weirs  of  the  several  reservoirs.  The  rain  falls  of  these  years  were 
respectively,  46.4,  48.5,  and  51  inches. 

In  1864,  1865,  and  1866,  to  date,  no  water  has  been  lost  over  the  waste 
weirs.  The  whole  of  the  water  has  been  utilized,  and  had  not  the  year  1865 
derived  some  assistance  from  the  collections  of  1864,  as  1864  did  from  1863, 
the  city  would  have  been  put  to  serious  inconvenience  for  want  of  water.  The 
rainfall  in  1864  was  39  inches;  in  1865,  34.8  inches;  and  for  the  first  five 
months  of  1866,  15.1  inches.  The  whole  amount  collected  in  1865  equalled 
23.35  inches,  being  67  per  cent,  of  the  rain  fall  of  that  year.  Of  this  13£  inches 
(8.3  million  gallons  per  day)  was  delivered  to  the  millers,  and  there  remained 
but  10  inches  available  for  city  use,  equal  to  an  average  of  6,176,865  gallons 
per  diem. 

Except  in  such  low  years  of  rain  fall  as  1864,  1865,  and  1866,  the  amount 
available  from  Rivington  for  city  use  frequently  reaches  an  average  of  9  and  10 
millions  of  gallons  per  diem,  and  when  the  water  overflows  from  the  reservoirs 
12  million  gallons  per  diem  could  occasionally  for  a  few  weeks  be  drawn  from 
that  source. 

The  amount  delivered  to  the  city  being  about  a  fixed  quantity  per  diem 
while  the  amount  available  from  Rivington  Works  is  (according  to  the  wet  or 
dry  season)  a  very  variable  quantity,  the  result  is  made  uniform  by  varying  the 
deliveries  from  the  wells,  lessening  the  latter  according  as  the  Rivington  water 
exceeds  its  low  water  or  minimum  rate.  In  other  words,  the  more  of  the  Riv- 
iugton  water  there  is  received,  the  less  pumping  power  is  requisite  at  the  wells, 


92  LIVERPOOL   WATER   WORKS. 

and  if  the  Rivington  water  yielded  thirteen  million  gallons  per  diem,  which  is 
the  present  rate  of  delivery  to  the  city,  the  entire  pumping  apparatus  could,  for 
the  time  being,  be  relieved  from  duty.  At  present  the  city  is  trained  through- 
out the  year  to  the  low  water  rate  of  consumption  due  to  low  seasons  of  rain  fall 
on  the  Rivington  district,  to  avoid  the  dissatisfaction  and  discomfort  which  would 
ensue  from  a  serious  reduction  of  the  supply  after  the  habits  of  the  people  had 
accommodated  themselves  to  the  larger  and  freer  use  of  water,  which  the  unre- 
stricted supply  of  a  wet  season  would  permit. 

The  accompanying  sketch  shows  the  arrangement  of  the  filters.   (Plate  14.) 

There  are  six  filter  beds,  and  two  clear-water  basins  for  receiving  the  filtered 
water.  These  basins  have  a  joint  capacity  of  12  million  gallons. 

Through  the  reservoir  embankment,  immediately  above  them,  there  are  two 
tunnels,  with  four  slide-gates  or  sluices  in  each.  The  one  tunnel  passes  off  the 
compensation  water  to  the  millers  ;  this  tunnel  draws  its  water  from  the  bottom 
of  the  reservoir.  The  other  tunnel  passes  off  the  portion  of  water  to  be  filtered 
and  sent  to  the  city  ;  this  tunnel  takes  its  water  from  a  point  14  feet  above  the 
bottom  of  the  reservoir. 

The  water  for  the  filters  flows  into  an  open  canal  or  race,  as  shown  on  the 
accompanying  sketch,  from  whence  it  is  drawn  at  will  upon  each  filter  bed. 
The  sand  surface  of  each  filter  measures  300  by  100  feet.  The  sides  are  sloped 
at  2  to  1,  and  paved  very  neatly  with  dimension-stone,  laid  dry.  To  prevent 
the  water  passing  through  the  joints  of  this  paving,  the  slopes  to  the  surface  of 
the  water  are  covered  with  sand. 

The  materials  of  the  filter  beds  consist  of  sand,  gravel,  and  broken  stone, 
in  the  following  proportions  : 

Fine  sand 30  inches. 

Fine  gravel 6  " 

Half-inch  gravel 6  " 

Three-quarter-inch  gravel 6  " 

One-inch  gravel 6  " 

Two-inch  cubes 9  " 

Broken  stone,  four-inch  cubes . . 24  " 

87  inches. 

Two  dry  rubble-drains,  situated  as  shown  in  the  accompanying  section,  run 
through  the  24-inch  course  of  cobble-stones,  and  collecting  the  filtered  water 
there,  carry  it  to  the  clear-water  basins,  as  shown  on  the  sketch-plan.  Four 
air-pipes  rise  from  each  of  these  drains  to  above  the  surface  of  the  water.  The 
bottom  of  the  filter  bed  is  puddled,  as  are  the  sides  under  the  coursed  paving. 
The  depth  of  water  on  the  filters  is  limited  to  two  feet.  The  ice  here,  the  Super- 


LIVERPOOL   WATER   WORKS.  93 

intendent  informed  me,  had  not  exceeded  one  inch  in  thickness  on  the  filter  beds, 
although  it  has  been  five  inches  thick  upon  the  reservoirs. 

At  the  time  of  my  visit  (August,  1866),  the  water  of  the  reservoir  was  19 
feet  below  its  full  water  line.  It  was  of  a  brownish  color  when  seen,  in  mass, 
but  apparently  held  little  or  no  sediment  in  suspension.  The  Superintendent 
informed  me  that  it  carried,  however,  sufficient  organic  matter,  apparently  vege- 
table and  very  minute,  to  gum  up  the  surface  of  the  filter  beds,  so  that  they 
required  to  be  cleaned  off  at  present  (the  whole  series)  ouce  a  fortnight.  When, 
in  addition  to  this,  the  water  is  turbid  from  floods,  the  beds  have  occasionally  to 
be  cleaned  once  a  week,  but  the  average  for  the  year  is  about  once  a  fortnight. 

The  fine  vegetable  matter  referred  to  is  most  troublesome   in  midsummer. 

The  depth  of  sand  pared  off'  during  the  year  by  these  repetitions  of  the  pro- 
cess of  cleansing  amounts  to  15  to  18  inches  from  each  bed.  This  sand  is  washed 
and  laid  aside,  to  be  replaced  once  a  year.  The  apparatus  for  cleansing  the  sand 
is  very  complete.  The  sand  is  moved  from  its  box  of  deposit  by  a  screen  into 
the  wash  trough,  is  moved  along  the  wash  trough  and  well  stirred  in  water  there 
in  the  same  way,  and  after  being  washed,  is  drawn  out  of  the  water  and  deliv- 
ered into  carts  by  a  similar  arrangement. 

The  cost  of  filtering,  as  stated  by  Mr.  Duncan,  the  Engineer,  averages  very 
nearly  £100  per  annum  for  every  million  gallons  filtered  daily — say,  $500  in  geld. 
This  is  at  the  rate  of  $1.37  (gold)  per  million  gallons  per  diem.  Each  filter  bed 
has  a  sand  area  of  30,000  square  feet.  The  six  filter  beds  have  a  sand  area  of 
180,000  square  feet.  As  the  beds  are  cleaned  one  by  one,  there  are  always  five 
of  them  in  use  ;  the  minimum  sand  area  in  use,  therefore,  is  150,000  square  feet. 
When  filtering  five  million  gallons  per  diem,  the  rate  for  five  filters  is  53?  imp. 
gallons  per  square  foot  per  diem.  This  may  be  considered  the  average  rate  at  the 
time  of  my  visit,  for  even  when  the  six  filter  beds  are  covered,  as  they  were  then, 
one  may  be  .assumed  to  be  nearly  ready  for  cleansing.  AVhen  the  five  filters  are 
passing  ten  million  gallons,  the  rate  is  665  gallons  per  square  foot,  and  with 
twelve  millions  it  would  be  80  gallons  per  square  foot  per  diem.  The  last-men- 
tioned rate  Mr.  Duncan  considered  to  be  in  excess  of  the  proportion  most  favor- 
able to  economy  in  the  process,  as  well  as  to  entire  limpidity  and  regularity  under 
all  states  of  the  water,  and  as  the  reservoir  facilities  in  this  region  will  have  to  be 
increased  to  meet  the  growing  demands  of  the  city,  it  is  contemplated  to  con- 
struct two  additional  filter  beds  at  this  place. 

Mr.  Duncan  is  of  opinion  that  an  average  of  one-half  cubic  foot  of  water  per 
square  foot  of  sand  surface  per  hour  should  never  be  exceeded,  and  that  a  better 
rule  would  be  to  limit  it  to  one-third  cubic  foot  of  water  per  hour.  The  first  is 
equivalent  to  75  imperial  gallons  per  square  foot  of  surface  per  diem,  and  the 
second  to  50  imperial  gallons. 

From  the  two  clear  water  basins  (c,  c,  on  the  sketch)  a  44-inch  pipe,  23 3 

J2 


94  LIVERPOOL   WATER   WORKS. 

miles  in  length,  carries  the  filtered  water  to  the  Kensington  reservoir  in  Liver- 
pool. 

This  reservoir  stands  225  feet  above  tide,  or  157  feet  below  the  clear-water 
basins  at  Rivington.  The  pipe  is  relieved  in  its  course  by  three  "balancing 
reservoirs,"  so  called  ;  small  basins  where  the  water  delivers  into  air,  and  the 
aggregate  pressure  due  to  the  difference  of  level  of  the  extreme  points  is  thus 
divided.  The  distances  of  these  relieving  basins  from  the  Rivington  basins,  and 
their  heights  above  tide,  are  as  follows  : — 


DISTANCE. 

HEIGHT 
ABOVE  TIDE. 

Aspell  Moor                ...         

3  miles. 

375  feet. 

Mountrey  House  

11     " 

328     " 

Prescott  

17      " 

280    " 

From  the  Prescott  basin  the  town  of  Prescott  is  supplied  with  water.  A  sup- 
plementary main  of  24  inches  diameter  is  also  carried  from  this  basin  to  Liver- 
pool. 

The  Kensington  reservoir  is  a  covered  reservoir  with  a  capacity  of  17  million 
gallons.  There  are  besides  four  other  covered  reservoirs  at  different  points  of 
the  city,  deriving  their  waters  from  the  44-inch  main,  or  from  the  Kensington 
reservoir.  These  have  a  joint  storage  capacity  of  9  millions,  so  that,  with  the 
Kensington  reservoir  the  reserve  in  store  in  the  immediate  neighborhood  of  the 
city  may  be  said  to  be  equal  to  two  days'  supply  at  the  present  rate  of  con- 
sumption. At  the  Audly  street  reservoir  there  is  a  pumping  engine  delivering 
water  into  an  iron  tank  there,  situated  80  feet  above  the  level  of  the. Kensington 
reservoir.  This  tank  has  a  capacity  of  250,000  gallons,  and  commands  certain 
pieces  of  high  ground  which  are  not  controlled  by  the  other  reservoirs. 

This  great  city  is  very  inadequately  supplied  with  water  at  present,  and 
looking  to  its  rapid  growth,  the  means  hitherto  depended  on  hardly  admit  of 
such  an  extension  as  will  satisfy  its  future  wants.  The  city  will  probably  be 
driven  to  seek  a  sufficient  supply  in  the  mountains  of  North  Wales,  as  suggested 
by  Mr.  Duncan  and  other  engineers  ;  but  until  the  proper  sources  of  supply  can  be 
determined  on,  and  until  it  can  be  made  available,  considerable  additions  will 
have  to  be  made  to  the  present  works  to  meet  the  current  requirements  of  the 
place. 

I  am  indebted  to  Mr.  Thomas  Duncan,  the  Engineer  of  the  Liverpool  Water 
Works,  for  the  information  which  I  have  sketched  above,  and  for  the  facilities 
afforded  me  to  understand  and  examine  the  works. 


EDINBURGH    WATER    WORKS.  95 


EDINBURGH  WATER  WORKS. 


EDINBUEOH,  My  and  August,  18G6. 

The  water  for  the  supply  of  the  City  of  Edinburgh  is  derived  from  the 
northern  slopes  of  the  Pentland  Hills,  a  mountain  range  I)' ing  to  the  south  and 
south-west  of  the  city.  The  Water  Company  supplies  from  the  same  sources  the 
adjoining  suburban  towns  of  Leith,  Newhaven,  and  Portobello. 

The  greater  part  of  the  water  is  derived  from  springs,  but  a  certain  por- 
tion of  it  is  obtained  from  the  small  mountain  brooks  of  the  same  district.  This 
last  portion  is  withdrawn  from  storage  reservoirs,  constructed  in  the  valleys  of 
these  brooks  to  collect  that  portion  of  the  flood  waters  which  would  otherwise 
run  to  waste.  A  determined  quantity  of  the  flood  water  thus  stored  up  is 
measured  out  to  the  brooks  day  by  day  throughout  the  year,  as  compensation 
to  the  mill  owners  below  for  the  springs  and  that  fraction  of  the  brook  water 
which  is  applied  to  city  use  ;  hence  they  have  been  called  compensation  reser- 
voirs, although,  with  three  exceptions,  they  serve  at  the  same  time  as  storage 
and  settling  reservoirs  for  that  portion  of  the  brook  water  made  use  of  for  the 
city. 

The  three  exceptional  reservoirs  alluded  to  are  strictly  "  compensation  reser- 
voirs," so  called  because  waters  stored  in  them  are  applied  solely  to  the  use  of 
the  mill  owners,  no  portion  of  it  being  drawn  off  for  city  use  ;  their  names  will 
be  given  further  oft. 

The  mill  owners  are  thus  in  reality  benefited  by  what  at  first  sight  would 
appear  to  be  their  loss.  In  other  words,  the  Water  Company  furnishes  the 
capital  necessary  to  store  up  their  surplus  mechanical  power  and  render  it  avail- 
able in  low  stages  of  the  water,  and  the  mill  owners  in  return  pay  the  Company 
in  kind,  that  is  with  a  certain  measure  of  water,  whether  from  springs  or  other- 
wise ;  in  the  last  three  cases,  solely  from  the  springs  of  the  district  in  which 
these  reservoirs  are  situated. 

The  history  of  the  Edinburgh  Works,  which  are  the  growth  of  four  sepa- 
rate stages  of  construction,  is  very  interesting.  It  will  be  found  detailed  in  a 
pamphlet  by  Mr.  Alexander  Ramsay,  the  Manager,  printed  in  1865.  I  give 
here  only  the  leading  features  as  of  interest  in  connection  with  the  filtering- 
works,  and  to  some  extent  explanatory  of  their  origin  and  necessity. 

The  first  stage  of  the  works  of  the  present  Water  Company,  and  the  most 
interesting,  as  standing  first  in  perfection  of  design  and  character  in  Great 
Britain,  at  the  time  of  its  conception,  was  completed  in  1822,  when  the  city 
became  thus  for  a  time  abundantly  supplied  with  pure  mountain  water. 


96  EDINBURGH    WATER   WORKS. 

The  water  was  obtained  from  that  portion  of  the  valley  of  Glencorse  brook 
which  lies  within  the  Pentland  range.  The  valley  is  narrow  here,  and  bounded 
with  steep  mountain  slopes. 

A  very  copious  spring,  called  the  Crawley  Spring,  occurs  at  the  mouth  of 
the  valley.  This  spring,  which  discharges  very  regularly  an  average  of  at  least 
60  cubic  feet  per  minute,  delivered  its  water  into  the  Glencorse  brook,  and  ren- 
dered the  flow  of  that  brook,  to  that  extent  at  least,  very  reliable  and  valuable 
to  the  owners  of  mill  property  down  the  stream.  The  Water  Company  obtained 
the  right  to  take  this  spring,  and,  in  order  to  compensate  the  mill  owners  for  its 
loss,  they  constructed  the  Glencorse  compensation  reservoir,  placed  about  half  a 
mile  above  the  outlet  of  the  spring. 

A  fountain-house  at  the  outlet  of  the  spring  receives  its  water  and  serves 
as  a  cistern,  with  which  the  pipe  which  conveys  the  water  to  Edinburgh  is  con- 
nected, and  from  which  it  is  supplied.  Into  the  same  fountain-house  a  certain 
portion  of  the  hill  or  Glencorse  water,  from  the  reservoir  above,  is  now  deliv- 
ered after  filtration.  Since  the  first  opening  of  the  works  in  1822,  the  embank- 
ment of  the  Glencorse  reservoir  has  been  twice  raised,  and  the  storage  capacity 
of  the  reservoir  largely  increased.  "  The  right  to  use  a  portion  of  the  reservoir 
water  for  the  city  followed  these  enlargements. 

From  this  point  an  underground  drain  was  run  up  the  valley  a  short  dis- 
tance, crossing  and  keeping  close  to  the  channel  of  the  brook.  The  object  of 
this  drain  was  to  secure  the  water  of  another  spring,  as  well  as  to  gather  a  por- 
tion of  the  brook  water  filtered  through  the  gravel  which  intervened  between 
the  brook  channel  and  the  tunnel.  The  tunnel,  however,  when  the  brook  was 
small  did  not  deliver  enough,  and  when  it  was  in  flood  did  not  deliver  the  water 
clear.  To  correct  the  last-mentioned  difficulty,  the  channel  of  the  brook  has 
been  since  diverted  away  from  the  line  of  the  underground  tunnel,  which  still, 
however,  collects  as  well  the  waters  of  the  small  springs  referred  to. 

The  pipe  which  conveys  the  water  to  Edinburgh  is  8  miles  in  length  (42,240 
feet),  and  varies  from  20  to  15  inches  in  diameter.  It  delivers  its  water  directly 
into  the  distributing  pipes  of  the  city,  its  governing  pressure,  however,  being 
limited  by  the  altitude  of  a  cistern  on  the  Castle  Hill  of  Edinburgh,  with  which 
it  is  connected,  and  into  which  its  surplus  water  overflows.  At  present  the 
Crawley  water  does  not  rise  to  the  level  of  this  cistern  during  the  clay,  but  during 
the  night  hours,  when  the  consumption  of  the  city  is  at  its  minimum,  it  over- 
flows into  this  cistern,  and  with  the  pipe  mains  from  other  quarters  of  the  Pent- 
land  range,  restores  to  the  cistern  what  has  been  drawn  off  from  it  during  the 
day.  The  other  pipes  communicating  in  the  same  way  with  this  cistern  are  the 
Comiston,  the  Swauston,  and  the  Colington  pipes.  The  cistern  holds  27  feet  of 
water  when  full.  Its  capacity  is  about  1,542,000  imperial  gallons.  The  Castle 
Hill  cistern  (a  small  covered  reservoir)  is  situated  225  feet  below  the  fountain- 
head  at  Glencorse,  and  320  feet  above  tide.  The  Engineer  calculated  that  the 


EDINBURGH    WATER   WORKS.  97 

pipe  would  deliver  253a  cubic  feet  per  minute.  The  delivery  now  is  given  as 
equal  to  253  cubic  feet  per  minute. 

At  the  opening  of  the  Works,  in  1822.  this  quantity  was  not  needed  in 
Edinburgh,  but  when  it  became  necessary  it  was  ascertained  that  during  certain 
exceptional  seasons  of  rain  fall  (more  especially  1842)  it  could  not  be  obtained. 
The  Glencorse  reservoir  was  found  then  insufficient  to  supply  at  the  same  time, 
the  amount  of  water  deliverable  to  the  millers  (130  cubic  feet  per  minute  at 
that  time),  and  the  wants  of  the  city.  .  Indeed,  for  a  short  period,  the  millers 
were  entirely  deprived  of  their  portion,  and  the  city  supply  reduced  to  80  cubic 
feet  per  minute. 

The  reservoir  at  that  time  had  a  capacity,  when  full,  of  about  30,000,000 
cubic  feet.  The  drainage  area,  applicable  to  Glencorse  reservoir,  amounts  to 
3, 69 4  acres. 

To  remedy  the  defects  above  mentioned,  the  dam  o/  this  reservoir  was 
further  increased  in  height,  and  its  capacity  increased,  and  a  new  storage 
reservoir  Avas  constructed  further  up  the  valley,  called  Loganlea  reservoir.  The 
drainage  area  was  not  modified  by  this  process,  but  the  ability  to  store  up  the 
flood  waters  was  largely  increased.  The  present  capacities  of  these  reservoirs 
are  as  follows : 

The  Glencorse  reservoir, 55,000,000  cubic  feet. 

The  Loganlea  reservoir, 19,000,000     " 


Total, 74,000,000  cubic  feet. 

The  Crawley  spring  must  be  in  part  derived  from  the  same  drainage  area. 

In  ordinary  years  of  rain  fall  the  whole  of  the  flood  water  is  not  collected 
by  these  reservoirs.  On  the  contrary,  a  very  large  portion  still  runs  to  waste  ; 
but  even  this  portion  of  the  flood  water  is  rendered  more  valuable  to  the  millers 
by  the  existence  of  the  reservoirs,  inasmuch  as  these  lakes  modify  importantly 
the  time  of  its  deliver)',  distributing  their  surplus  flood  waters  over  days  instead 
of  hours. 

In  1863,  when  the  rain  fall  was  39.3  inches,  the  amount  wasted  over 
Glencorse  waste  weir,  as  ascertained  by  daily  gaugings,  was  254  millions  cubic 
feet,  being  45  per  cent,  of  the  rain  fall  of  that  year.  On  the  other  hand,  I  have 
been  informed,  that  during  at  least  one  year  of  very  low  rain  fall,  the  Glencorse 
reservoir  has  not  been  quite  filled,  showing  that  during  that  year  the  whole  of 
the  flood  water  was  utilized. 

Mr.  Ramsay,  in  his  paper  on  the  rain  fall  of  the  Glencorse  district,  gives 
the  amounts  delivered  to  the  city  and  to  the  millers,  from  the  reservoir,  as  equal 
to  the  following  inches  of  rain  fall : 


98  EDINBURGH    WATER   WORKS. 

1.  Appropriated  to  town  supply, 8. 150  inches. 

2.  In  supply  to  mills 7 . 071 


Total  utilized  by  the  reservoir, 15 . 22  inches. 

The  surplus  of  any  rain  fall  over  these  figures  is  one  part  lost  by  evaporation 
and  absorption,  and  the  residue,  if  any,  passed  over  the  waste  weir  into  the 
Glencorse  burn.  The  amount  passed  over  the  waste  weir,  in  1863,  Mr.  Ramsay 
makes  equivalent  to  18.964  inches  of  rain,  and  the  portion  lost  by  absorption 
and  evaporation  as  5.115  inches,  stating  that  the  ground  was  maintained  very 
moist  throughout  that  year,  in  which,  consequently,  the  loss  represented  by  the 
5 . 1  inches  would  be  due  mainly  to  evaporation. 

The  waste  weir  of  the  reservoir  is  sixty  feet  wide.  The  water  passing  over 
it  after  very  heavy  rains,  the  reservoir  being  full,  occasionally  reaches  to  12 
inches  in  depth.  On  one  occasion  of  unusually  severe  rain  fall,  when  some 
bridges  were  carried  away  on  other  streams,  the  depth  flowing  over  the  waste 
weir  rose  to  24  inches. 

The  pipe  from  the  Crawley  fountain-head  delivers  now  its  full  complement 
of  water,  consisting  of : 

From  Crawley  spring, 60  cubic  feet  per  minute. 

From    Glencorse  brook,   through  its 

reservoir 193  " 


Total  to  the  city, ....... .....    253 

The  water  delivered  to  the  millers 
since  the  construction  of  the  Logan- 
lea  reservoir  amounts  to  a  uniform 
rate  of. .  220 


Total, 473  cubic  feet  per  minute. 

I 

The  reservoirs  are  responsible  for  the  delivery  of  this  quantity,  estimated  by 
Mr.  Ramsay  as  equivalent  to  15 . 22  inches  of  the  yearly  rain  fall.  That  portion 
of  the  water  drawn  from  the  reservoir  for  city  use  is  filtered. 

When  the  Glencorse  reservoir  is  full,  the  water  for  the  city  is  drawn  off  by 
means  of  a  pipe  whose  mouth  is  situated  20  feet  below  high  water  of  the 
reservoir,  while  the  portion  of  water  deliverable  to  the  millers  is  drawn  off  lower 
down,  at  a  point  53  feet  below  full  water  of  the  reservoir.  With  the  reservoir 
full,  the  water  within  control  of  the  city  pipe  is  clear  and  could  be  used  without 
filtration,  except  as  filtration  benefits  river  water,  under  any  circumstances,  by 
depriving  it  of  the  floating  organisms  before  referred  to.  When,  however,  the 
reservoir  water  has  fallen  below  the  mouth,of  the  pipe  alluded  to,  the  portion 


EDINBURGH  WATER  WORKS,  99 

required  for  the  city  is  drawn  from  the  same  low  point,  as  that  delivered  to  the 
millers,  and  that  point  being  near  the  bottom,  the  water  is  liable  to  pass  off 
there  more  or  less  turbid.  Under  this  condition  of  things  the  filters  become 
specially  necessary  to  remove  the  sedimentary  discoloration. 

There  are  three  filter  beds  in  the  bottom  of  the  valley,  situated  a  short  dis- 
tance below  the  reservoir  embankment.  Through  the  kindness  of  the  Engineer, 
Mr.  Leslie,  I  am  enabled  to  give  the  details  of  construction  of  these  filter  beds, 
and  I  refer  to  the  accompanying  sketch  as  explanatory  of  these.  (Plate  XV.) 

When  a  filter  bed  is  bare  the  water  is  let  on  from  six  pipes,  each  controlled 
by  a  stopcock.  The  surface  of  the  sand  is  waved,  so  that  the  water  rises  upon 
the  bed  without  producing  any  sensible  current  on  the  sand.  When  the  water 
has  to  be  drawn  off  for  cleansing  the  filter  bed,  the  waste  pipe  enables  the  at- 
tendant to  draw  off  directly  the  lower  and  most  turbid  portion  of  the  water. 

The  reservoir  has  not  been  so  low  for  some  years  as  to  deliver  turbid  water  ; 
the  filter  beds  are  not  cleansed  (according  to  the  attendant),  except  at  long  inter- 
vals, at  present  not  oftener  than  once  in  six  months.  The  attendants  assume 
that  from  the  apparent  purity  of  the  water  there  is  little  or  nothing  to  intercept, 
but  in  this  I  believe  them  to  be  mistaken.  The  difference  in  level  between  the 
water  on  the  filter  beds  and  the  water  in  the  clear-water  well,  said  to  be  four 
feet  at  the  time  of  my  visit,  showed  that  the  surface  of  the  sand  was  more  or 
less  choked,  since  with  clean  sand  a  head  of  twelve  inches  would  have  passed  the 
water  through  the  filters.  The  fact  that  the  water  had  at  several  times  broken 
through  the  filtering  materials  into  the  drains  below  was  evidence  in  the  same 
direction.  The  sand  of  the  filter  beds  was  all  but  choked  on  its  surface,  and  an 
unusual  head  became  necessary  to  force  the  water  through,  which  would  tend  to 
break  into  well-holes  at  the  weakest  spots. 

The  materials  of  the  beds  are  as  follows  : — 

Fine  sand 18  inches. 

Coarse  sand 6     " 

Shells 6     " 

Fine  gravel 6     " 

Coarse  gravel 18  to  24  inches. 

This  is  the  depth  of  material  over  the  collecting  drain,  which  is  18  inches  deep 
by  24  wide,  and  surrounded  by  coarse  gravel.  From  the  collecting  drain  six 
clay  pipes  of  6  inches  diameter  each  extend  on  either  side  to  the  foot  of  the  slope. 
The  collecting  drain  carries  the  water  to  a  measuring  well,  where  the  proper 
amount  passes  off  to  the  Crawley  fountain-house  for  the  city  supply.  The  usual 
depth  of  water  over  the  filter  beds  is  four  feet.  It  was  from  4£  to  5  feet  at  the 
time  of  my  visit. 

The  sand  surface  of  each  of  these  filter  beds  measures  90  X  90  feet,  equal  to 


100 


EDINBURGH   WATER   WORKS. 


8,100  superficial  feet.  There  are,  therefore,  24,300  square  feet  in  three  filters. 
The  amouut  deliverable  by  the  Edinburgh  pipe  is  limited  to  253  cubic  feet  per 
minute,  but  of  this  amount,  173  to  193  cubic  feet  only  is  receivable  from  the 
reservoir,  equal  to  at  most  2,078,974  U.  S.  gallons  per  diem  ;  the  remaining  60 
to  80  c.  feet  of  spring  water  is  received  below  the  position  of  the  filter  beds. 
The  maximum  rate  of  filtration,  then,  with  the  three  filters  in  use,  would  be  85?z 
U.  S.  gallons  per  square  foot  per  diem.  With  but  two  filters  in  use  during  the 
time  that  the  third  is  being  cleansed,  the  rate  of  filtration  would  reach  128  U.  S. 
gallons  per  square  foot  per  diem. 

The  portion  of  the  Edinburgh  supply  derived  from  the  Glencorse  valley 
consists  thus  of  one  part  of  spring  water  and  three  parts  of  filtered  brook  water. 
The  actual  supply  to  Edinburgh  now  from  all  sources,  as  well  as  its  progressive 
increase,  will  be  understood  from  the  following  table  obtained  from  Mr. 
Ramsay's  paper  and  descriptions. 


Population 
supplied. 

Imperial  Gallons 
per  head. 

Delivery, 
cubic  feet  per 
Minute. 

1842  

166,878 

13  41 

249  5 

1848  

185,806 

22.21 

460  06 

1852     

195,984 

23  74 

518  68 

1856  

199,782 

25  17 

560  40 

1862  

207,381 

30  38 

702  30 

1863     

208,647 

31  20 

731  80 

1869         

220,000 

40 

992  00 

The  additional  works  under  construction  in  1866,  and  completed  in  1868, 
have  increased  the  supply  to  992  cubic  feet  per  minute  ;  this  is  equal  to 
8,900,894  imperial  gallons,  or  10,685,770  U.  S.  gallons  per  diem. 

The  cost  of  the  works  was  given  by  Mr.  Ramsay,  in  1866,  at  £500,000, 
equal  to  two  and  a  half  million  of  dollars  in  specie. 

The  amounts  of  population  given  above  include  Leith,  Portobello,  and  the 
village  of  Newhaven.  The  returns  of  1861  give  their  respective  populations  as 
follows  : 

Edinburgh 1 63,121 

Leith 33,628 

Portobello 4,366 

Newhaven,  not  given,  probably 2.000 

203,115 


EDINBURGH    WATER   WORKS. 


101 


Without  attempting  to  trace  the  separate  constructions  in  their  order, 
which  have  produced  the  progressive  increase  in  the  supply,  I  will  here  give 
the  names  of  all  the  springs  and  reservoirs  belonging  to  this  Water  Company. 


SPRINGS. 


NAME  OF  SPBIKO. 

Average  Yield  in 
cubic  feet 
per  Minute. 

Brought  in 
Year. 

1    Crawley  Spring     •          

60  to  80 

1822 

2    I3avelaw  Springs       ...        

1 

3    Listen  Sliiels  Springs  

[•           150 

1847 

4.  Black  Springs        

5    Colycuni  Springs  

200 

1858 

6    Crosswood  Springs  

70 

1868 

RESERVOIRS. 


NAME. 

Capacity, 
cubic  leet. 

Rate  of 
Delivery  to 
Mill  Owners, 
cubic  feet 
per  Minute. 

Applied  to  City 
use. 

1.  Glencorse.        

55,000,000 

) 

4.  Logan  Lea     

19,000,000 

{•     220 

193 

2.  Threepmuir  

33,000,000 

All. 

3.  Harlaw  

26,000,000 

All. 

8,000,000 

"j 

Overplus. 

6    Chubbiedean  

10,000,000 

I       60 

Overplus. 

7.  Torduff  

19,000,000 

Overplus. 

8  

85,000,000 

All. 

9.  Crosswood  

25,000,000 

All. 

The  covered  cistern  on  the  Castle  Hill  receives  all  these  waters,  and  com- 
mands by  its  height  ail  the  dwellings  within  the  city,  with  the  exception  of  the 
castle  and  a  few  houses  in  its  vicinity.  It  is  capable,  when  full,  of  holding  about 
one  million  and  a  half  imperial  gallons. 

To  meet  the  wants  of  the  houses  at  the  head  of  the  High  street,  and  the 
dwellings  within  the  Castle  limits,  an  iron  cistern  has  been  placed  upon  the 
highest  ground  of  the  Castle  rock,  capable  of  holding  100,000  imperial  gallons. 

13 


102       .  EDINBURGH   WATER   WORKS. 

This  cistern  is  in  two  divisions  ;  the  one  applicable  to  the  Castle  buildings,  the 
other  to  the  highest  buildings  outside  of  the  Castle.  This  cistern  is  filled  by 
the  Swanston  pipe. 

At  Torduff  there  are  three  filter  beds,  designed  to  filter  the  brook  water  col- 
lected on  that  side  of  the  Pentland  slopes.  It  is  but  rarely,  however,  that  there 
is'.oec&sion  to  use  them,  the  water  drawn  off  from  the  reservoirs  in  that  vicin- 
ity being  very  rarely  discolored  by  sedimentary  or  other  foreign  matters. 
';i ..:."•  The  relation  of  these  new  reservoirs  to  their  respective  drainage  areas,  and 
the  percentage  of  rain  fall  which  can  be  gathered  and  depended  on  will,  it  is 
hoped,  be  communicated  to  the  public  at  some  future  time. 

The  original  works,  then  confined  to  the  Glencorse  valley,  as  well  as  their 
first  enlargement,  were  designed  by  Mr.  James  Jardone,  a  man  whom  all  engi- 
neers agree  to  honor,  and  constructed  under  his  immediate  superintendence. 
The  subsequent  enlargements  have  been  made  under  the  immediate  directions 
of  Mr.  James  Leslie  ;  Messrs.  Kendall  and  Beardmore  having  in  one  case  been 
joined  with  him  as  Parliamentary  Engineers.  Mr.  Leslie  is  at  present  the  Engi- 
neer of  the  Company. 


DUBLIN  WATEU  WORKS.  103 


DUBLIN  WATER  WORKS, 


DUBLIN,  August,  1866. 

The  city  of  Dublin  receives  its  supply  of  water  at  present  from  two  canals, 
which  terminate  on  tide  water  here,  and  from  the  river  Dodler,  by  an  open  con- 
duit. The  river  Liffey  runs  through  the  centre  of  the  city,  and  at  present  receives 
its  sewerage,  but  does  not  contribute  to  its  water  supply.  The  north  side  of  the 
city  is  supplied  from  the  Royal  Canal,  and  the  south  side  from  the  Grand  Canal 
and  from  the  Dodler  water  lead.  All  these  sources  of  supply  are  said  to  be 
exposed  to  a  variety  of  polltiuons  ;  they  will  be  entirely  dispensed  with  when 
the  works  now  under  construction  are  completed.* 

The  population  to  be  supplied  by  the  new  water  works  is  estimated  at 
304,000.  The  consumption  of  water  at  present  is  said  not  to  exceed  six  mil- 
lion gallons  daily. 

The  new  works  have  been  under  construction  during  the  last  four  years, 
and  are  expected  to  be  sufficiently  completed  this  season  to  admit  of  the  intro- 
duction of  the  new  water.  This  supply  is  to  be  drawn  from  the  upper  branches 
of  the  river  Vartry,  a  clear  mountain  stream,  whose  sources  are  found  on  the 
southern  slopes  of  the  great  Sugar  Loaf  mountain,  and  the  eastern  slopes  of 
the  Djouce  mountain.  The  rocks  of  this  region  are  granite,  mica-schist,  and  a 
very  hard  clay  slate,  and  the  water  is  stated  to  be  very  soft  in  character.  The 
ground  was  selected  by  Mr.  Hawkshaw,  and  the  scheme  is  founded  upon  his  gen- 
eral plans.  The  works  are  being  constructed  under  the  directions  of  Mr.  Parke 
Neville,  the  Engineer  to  the  Corporation  of  Dublin. 

These  new  works  consist  of  a  large  collecting  reservoir  in  the  valley  of  the 
Vartry,  a  system  of  filter  beds  near  to  this  reservoir,  two  distributing  reservoirs 
within  five  miles  of  Dublin,  and  the  pipe  mains  connecting  the  collecting  reser- 
voir with  the  distributing  reservoirs  and  with  the  city. 

The  collecting  reservoir,  named  the  Round  wood  reservoir,  is  distant  25  miles 
from  the  city  of  Dublin.  An  embankment  has  been  formed  across  the  valley  of 
the  Vartry  here,  66  feet  in  depth  at  the  deepest  point,  and  about  2,000  feet  in 
length.  The  embankment  is  28  feet  wide  at  the  top,  with  a  slope  of  3  to  1  on  the 
inside,  and  of  2z  to  1  on  the  outside  of  the  bank.  The  inside  is  pitched  with  dry 

*  April,  1869,  they  are  now  completed  and  in  use. 


104  DUBLIN   WATER   WORKS. 

stone,  18  inches  thick  at  top.  and  12  inches  at  the  foot  of  the  slope.  The  pitch- 
ing rests  upon  a  bed  of  small  stone,  12  inches  thick.  An  arched  tunnel  (14x14) 
founded  on  the  solid  rock  passes  through  the  bank.  A  stone  screen  or  piece- of 
solid  masonry,  20  feet  thick,  built  within  and  across  the  tunnel,  separates  the 
water  end  of  this  tunnel  from  the  land  end.  Two  pipe  mains  pass  through  this 
screen  ;  one  of  33-inch  diameter,  and  one  of  48-inch.  The  33-inch  main  is  con- 
nected with  a  water  tower  situated  inside  the  reservoir,  having  three  pipe  con- 
nections through  the  tower,  at  the  heights  of  10,  20,  and  30  feet  from  its  high 
water.  The  48-inch  pipe  commands  the  lowest  point  of  the  reservoir  and  forms 
a  waste  pipe  to  admit  of  the  water  being  drawn  off  to  bottom  if  required.  In 
any  emergency  requiring  a  rapid  discharge  of  the  water,  the  33-inch  pipe,  by  a 
branch,  can  be  used  in  the  same  way. 

Although  the  33-inch  pipe  is  the  one  intended  for  the  service  of  the  filter 
beds,  the  48-inch  pipe  has  a  connection  with  it,  by  which  the  water  from  the 
lower  portion  of  the  reservoir  can  as  well  be  delivered  to  the  filter  beds,  when 
necessary. 

At  the  lower  end  of  the  tunnel  there  are  two  valves  on  the  33-inch  pipe, 
and  one  valve  on  the  48-inch  pipe.  The  33-inch  valve  is  divided  into  two  slides 
or  plates,  the  48-inch  valve  into  three  slides.  Each  of  these  slides  works  inde- 
pendent of  the  other.  The  force  required  to  move  them  is  thus  very  much 
reduced,  and  they  are  more  under  command  and  more  easily  kept  in  good  con- 
dition than  the  ordinary  single  disk  valves.  The  greatest  depth  of  water  in  the 
reservoir  when  full  will  be  sixty  feet.  The  water  area  of  the  reservoir  is  409 
acres.  It  is  calculated  to  hold  2,400  million  imperial  gallons  of  jvater.  A  waste 
weir  of  300  feet  in  length  carries  off  any  surplus  water,  delivering  it  by  means 
of  a  by-wash  into  the  Vartry  valley  below,  over  a  rock  slope  and  entirely  clear 
of  the  works. 

The  drainage  area  commanded  by  this  reservoir  measures  13,992  acres,  or 
22  square  miles  nearly.  No  observations  had  been  made  of  the  rain  fall  within 
this  region  previous  to  the  construction  of  the  works.  Observations  made  since 
their  commencement  give  the  following  averages  over  this  area  : 

1861 60.87  inches. 

1862 60.48      " 

1863 44.85      " 

1864 48.39      " 

1865 

In  the  narrow  valley  immediately  below  the  embankment  the  filter  beds  are 
placed.  The  33-inch  main  from  the  reservoir  is  carried  into  a  circular  basin  88 
feet  in  diameter.  Whatever  the  height  of  the  water  in  the  reservoir,  the  water 


DUBLIN    AVATER   WORKS.  105 

in  this  basin  can  always  be  maintained  at  a  uniform  height  by  adjusting  the  tun- 
nel valve  accordingly.  From  this  circular  basin  the  water  is  carried  by  two 
open  drains  to  the  filter  beds,  connecting  with  each  by  a  pipe  and  stopcock. 
There  are  seven  filter  beds,  the  positions  arid  arrangement  of  which  will  be  un- 
derstood by  reference  to  the  accompanying  sketch  (Plate  16).  At  the  time  of 
my  visit  (August,  1866)  one  of  the  filter  beds  was  completed  ;  on  another  the  fil- 
tering materials  were  being  deposited  and  arranged,  the  others  were  in  various 
stages  of  construction,  but  not  quite  so  far  advanced.  There  are  two  open  basins 
for  the  reception  of  the  water  after  filtration.  The  two  basins  when  full  will 
hold  2,730,000  gallons.  Three  of  the  filter  beds  lie  on  the  south  side  of  these 
basins,  and  four  on  the  north  side. 

Each  of  the  filter  beds  communicates  with  the  one  or  the  other  of  these 
basins  by  a  passage  which  can  be  sluiced  off  at  discretion.  The  bottom  of  each 
filter  bed,  when  not  solid  rock,  is  puddled  with  a  layer  of  clay  puddle  two  feet 
thick.  The  sides  are  sloped  at  1  to  1,  with  9-inch  dry  pitching.  The  materials 
of  the  filters  are  as  follows  : 

Sand 30  inches. 

Fine  gravel,  pea  size 0      " 

Coarse  gravel,  nut  size 6       " 

Broken  stone,  3-inch  ring 6      " 

Clean  quarry  spauls,  5  to  8  inch 30 

78  inches. 

The  quarry  spauls  rest  on  the  puddle.  Resting  on  the  puddle  and  imbed- 
ded in  the  layer  of  large  stones  last  mentioned,  are  two  dry  stone  drains  (30x24 
each)  to  collect  the  filtered  water.  These  are  united  at  one  end,  as  shown  in 
the  sketch. 

Each  filter  bed  measures  213x115  feet  at  top  of  its  slopes.  At  the  surface 
of  the  sand  it  measures  203x105.  The  sand  area  of  each  is  therefore  21,315 
square  feet.  The  depth  of  water  over  the  filter  bed  is  limited  to  24  inches. 
Six  of  these  filters  are  supposed  to  be  always  serviceable,  the  seventh  undergo- 
ing the  process  of  cleansing. 

Although  the  amount  of  water  used  in  the  city  now  does  not  exceed  six 
million  gallons,  the  character  of  the  Vartry  water  is  so  superior  to  that  of  the 
canal  water  in  use  now,  that  the  consumption  will  in  all  probabilitj7  reach  nine 
millions  shortly  after  the  completion  of  the  works. 

With  six  of  the  filter  beds  in  use  (127,890  square  feet),  and  a  consumption 
of  nine  million  gallons  per  diem,  the  rate  of  filtration  would  be  70  gallons  per 
square  foot  of  sand  surface  per  diem.  With  a  consumption  of  twelve  millions 
the  rate  would  be  93  gallons  per  square  foot  per  diem. 


106  DUBLIN  WATER  WORKS. 

The  ample  receiving  reservoirs  at  Stillorgan  will  enable  the  filter  beds  to 
be  operated  continuously  night  and  day.  The  large  size  of  the  collecting  reservoir 
will  insure  great  freedom  from  sediment  at  its  lower  end,  for  probably  the  first  3(5 
feet  of  its  water.  From  that  level  downwards  the  water  may  be  expected  to  be 
rendered  more  or  less  turbid  by  floods.  The  filter  beds  are  intended  to  be  used 
during  all  stages  of  the  water  ;  but  when  the  reservoir  is  full  their  duty  will  be 
mainly  confined  to  the  separation  of  floating  organic  matters,  vegetable  or  ani- 
mal. All  vegetable  fibre,  seeds,  small  fish,  an/l  the  water  insects  upon  which 
they  feed,  are  intercepted  by  the  filters,  and  this  forms  a  very  important  part  of 
their  duty  during  the  summer  stages  of  all  rivers.  When  the  reservoir  gets  low 
and  the  water  becomes  turbid  from  floods,  the  filter  beds  will  be  more  severely 
taxed. 

The  city  pipe  main  which  conveys  the  water  to  the  tunnel  below  (hereafter 
mentioned)  has  an  independent  connection  with  each  of  the  pure  water  basins, 
marked  C  C  on  the  sketch.  It  has  also  a  connection  with  the  reservoir  pipe,  to 
admit  of  the  water,  if  needful,  being  passed  on  directly  to  the  city  without  fil- 
tration. 

The  height  of  the  full  water  of  the  reservoir  is  692  feet  above  ordnance 
datum  (which  assumed  base  is  the  level  of  low  water  of  a  12-foot  tide  in  Dublin 
harbor).  The  height  of  the  water  in  the  pure  water  basins  will  be  about  620 
feet  above  the  same  datum,  and  518  feet  above  the  highest  street  in  Dublin. 
From  the  pure  water  basin  a  42-inch  pipe,  2,100  feet  in  length,  conducts  the 
water  to  a  tunnel  4,367  yards  in  length,  which  passes  through  a  mountain  spur 
here  of  hard  gneiss  rock.  At  the  lower  end  of  the  tunnel  there  is  a  relieving 
basin  and  measuring  weir,  where  the  water  for  the  supply  of  the  city  can  be 
gauged  daily.  This  basin  or  tank  is  606  feet  above  ordnance  datum. 

From  the  tank  a  33-inch  main  conveys  the  water  to  the  distributing 
reservoirs  at  Stillorgan. 

The  length  of  this  main  is  16*  miles,  and  the  height  of  the  first  of  the  two 
distributing  reservoirs  above  datum  is  274  feet. 

From  the  tunnel  tank  to  the  distributing  reservoir  there  is,  therefore,  a  fall 
of  332  feet. 

The  33-inch  pipe  follows  the  irregularities  of  the  intervening  ground.  To 
relieve  it,  however,  from  the  great  pressure  to  which  it  would  otherwise  be  sub- 
ject, it  opens  to  the  air  at  three  intermediate  points  on  its  length,  situated 
respectively  473,  414,  and  341  feet  above  the  ordnance  datum.  At  each  of 
these  points  there  is  a  small  open  basin,  into  which  the  pipe  delivers.  From 
the  opposite  side  of  the  basin  a  mouth-piece,  with  stopcock  and  self-acting 
valve  attached,  delivers  the  water  into  the  next  section  of  the  pipe.  Under 
this  arrangement,  each  section  of  the  pipe  is  subjected  only  to  the  pressure 
which  prevails  between  two  of  these  small  tanks  or  basins. 


DUBLIN  WATER  WORKS. 


107 


The  33-inch  pipes  are  cast  in  lengths  of  12  feet  5  inches,  and  are  of  eight 
different  weights,  the]  least  corresponding  with  a  thickness  of  g  inch,  and  the 
heaviest  with  a  thickness  of  IT?  inch,  the  intermediates  varying  by  six- 
teenths, viz.  : 


Inch. 

cwt 

qrs. 

Ibs. 

Ibs. 

!••                            •'• 

34 

2 

o 

Q  QKA 

if  

36 

3 

o 

411fi 

1  

39 

0 

16 

4384 

l'  .. 

41 

2 

o 

A  f\A(] 

liV- 

44 

o 

0 

4QOQ 

1A.. 

46 

2 

n 

ft  OfiO 

1*    . 

48 

3 

8 

K  Ai\Q 

1-nr-. 

51 

1 

n 

5rjA(\ 

At  Stillorgan  there  are  two  distributing  reservoirs  ;  the  one  situated  274 
feet,  and  the  other  271  feet  above  the  common  datum.  The  water  of  the 
lower  reservoir  stands  191  feet  above  the  highest  ground  in  the  city.  The  two 
reservoirs  have  a  water  area  of  18  acres,  and  a  capacity,  when  full,  of  about 
110  million  imperial  gallons. 

Two  pipe  mains,  of  27  inches  diameter  each,  convey  the  water  over  a 
distance  of  41  miles  to  Dublin. 

The  works,  when  finished,  are  estimated  to  cost  about  £400,000  (equal  to 
about  $2,280,000  in  gold).  The  supply  which  they  can  control  in  the  present 
state  will  not  exceed,  so  far  as  I  can  judge,  a  rate  of  from  12  to  14  million 
gallons  per  diem. 

I  am  indebted  to  a  descriptive  pamphlet  by  Mr.  Neville,  and  to  the  Resi- 
dent Engineer,  Mr.  Pallas  (who  accompanied  me  over  the  works),  for  much  of 
the  information  given  above. 


108  PERTH    WATER   WORKS. 


PERTH  WATER  WORKS. 


NATURAL    FILTER 

The  city  of  Perth  lies  on  the  right  bank  of  the  river  Tay,"a  large  and  rapid 
stream,  whose  sources  are  widely  spread  on  the  mountain  slopes  dividing  Perth- 
shire from  the  counties  of  Argyle  and  Inverness.  The  lochs  or  lakes  Erracht, 
Rannoch,  Tummel,  and  Tay,  gather  a  portion  of  its  head  waters,  and  act  as  stor- 
age reservoirs  to  the  river,  whose  channel,  in  the  driest  months  of  summer,  must 
on  this  account  be  more  than  usually  well  supplied  with  fine  water. 

The  mountain  slopes  referred  to  are  mostly  composed  of  gneiss  granite, 
and  mica  slate,  and  the  waters  shed  from  them  are  soft  and  pure  accordingly. 

Near  the  lower  boundary  of  the  city  the  upper  end  of  a  long  island  in  the 
river,  composed  entirely  of  gravel,  has  been  taken  advantage  of  to  construct  what 
is  called  a  natural  filter.  The  island  referred  to  leans  towards  the  left  bank 
of  the  Tay,  leaving,  as  the  accompanying  sketch  shows,  but  a  small  chan- 
nel between  it  and  the  main  land  on  that  side.  The  main  channel  of  the 
river  passes  between  the  island  and  the  city. 

On  the  island  above  mentioned  an  underground  tunnel  has  been  constructed, 
situated  parallel  with  the  river  shore  and  about  100  feet  from  it. 

The  bottom  of  this  tunnel,  as  near  as  I  could  learn,  is  about  30  inches 
below  the  low  summer  water  of  the  Tay.  The  length  is  300  feet.  For  250 
feet  of  this  length  the  tunnel  is  4  feet  in  width  inside,  and  8  feet  in  height. 
The  bottom  is  not  paved,  but  open  to  the  coarse  gravel  of  which  the  island  is 
composed. 

The  side  walls  are  of  stone,  laid  dry.  The  top  is  covered  with  paving 
stone.  This  forms  the  tunnel  as  originally  built.  It  was  afterwards  extended 
50  feet  at  its  upper  end,  but  the  extension  was  described  to  me  as  being  only 
of  half  the  dimensions  of  the  main  tunnel.  About  midway  of  the  tunnel  a  cir- 
cular well,  8  feet  in  diameter,  comes  to  the  surface,  and  forms  a  man-hole  of 
descent  for  examination  and  repairs.  From  the  bottom  of  this  well  two  lines 
of  12-inch  pipes,  each  550  feet  in  length,  proceed,  and  are  laid  across  the  bed  of 
the  river  to  the  engine-house  well,  situated  as  shown  on  the  sketch.  The  upper 
pipe  is  the  only  one  now  in  use  ;  the  lower  one,  which  had  been  rendered 
useless  by  the  construction  of  the  railroad  bridge,  is  now  being  repaired  and 


PERTH    WATER   WORKS.  109 

made  serviceable,  the  delivery  of  but  one  pipe  having  been  found,  at  certain 
stages  of  the  river,  insufficient  to  supply  adequately  the  pump  well. 

At  the  time  of  my  visit,  July,  1866,  it  was  low  water  of  the  river,  and  the 
stream  was  within  3  inches  of  its  lowest  stage.  There  was  at  this  time,  as  near 
as  I  could  judge,  24  inches  of  water  in  the  tunnel  ;.the  draft  upon  it  appeared 
moderate  and  the  water  clear  and  limpid.  The  water  in  the  river  was  not  turbid 
at  the  time,  but  it  was  brownish  in  color.  The  water  which  niters  through 
the  island  of  gravel  into  the  tunnel  was  &tated  to  be  always  clear,  whatever 
might  be  the  condition  of  the  river.  The  Superintendent  thought  that  the 
draft  from  it  might  be  doubled  without  impairing  its  quality.  The  difference 
in  level  between  the  surface  water  of  the  river  and  the  surface  water  in  the 
tunnel  was  stated  not  to  exceed  from  three  to  six  inches.  The  gravel  and 
sand,  through  which  the  water  passes  to  reach  the  tunnel,  must,  therefore,  be 
very  free. 

The  depth  of  water  in  the  tunnel  varies  with  the  level  of  the  water  in  the 
river.  The  city  of  Perth  lies  at  the  head  of  tide  water  of  the  Tay,  and  the  rise 
of  the  tide  at  this  place  is  from  4  to  6  feet,  the  depth  of  water  in  the  tunnel 
corresponding.  The  water,  however,  is  not  brackish  here  at  any  stage  of  the 
tide,  the  long  and  tortuous  channel  between  the  sea  and  this  point  preventing 
the  salt  water  from  being  felt  at  Perth. 

The  population  of  Perth  numbers  27,000.  The  daily  supply  of  water  to 
the  city  now  was  stated  by  the  Superintendent  to  average  200,000  gallons,  a 
very  low  rate  of  supply  for  the  population,  showing  that  wells  must  still  be  used 
by  man}r.  All  of  this  amount  is  derived  from  the  filtering  tunnel. 

If  we  take  the  open  bottom  of  this  tunnel  as  the  measure  of  its  rate  of 
nitration,  which  is  the  usual  practice,  it  gives  (-Trtra-)  182  gallons  per-  square 
foot  of  bottom  per  diem  ;  but  the  dry  stone  side  walls  must  increase  the  effective 
bottom,  say  to  6  feet  in  width  instead  of  4,  giving  a  rate  of  121  per  square 
foot  per  diem. 

We  should  fear  that  any  great  increase  of  this  rate  would  draw  with  it  sand 
into  the  tunnel.  The  tunnel,  however,  admits  of  being  lengthened  both  up 
stream  and  down  stream,  and  the  supply  can  consequently  be  largely  increased 
at  discretion. 

The  filtering  tunnel,  it  will  have  been  understood,  is  on  the  left  side  of  the 
main  channel.  The  engine-house  is  situated  on  the  right  bank  of  the  river,  and 
the  connection  between  the  two  is  made  by  the  12-inch  pipe  already  mentioned. 
There  are  two  pumping  engines  here,  and  a  well  to  each  engine,  supplied  by  the 
pipe  from  the  filter  gallery.  This  well  has  not  been  laid  low  enough  to  secure 
a  sufficiently  rapid  supply  to  the  pumps  when  the  river  is  low  ;  the  head,  then,  or 
the  difference  of  level  between  the  mouth  of  the  pipes  in  the  filter  gallery  and  the 
bottom  of  the  well,  is  insufficient.  This  defect  is  expected  to  be  remedied  by  the 

H 


110  PERTH    WATER   WORKS. 

second  pipe.  In  tlic  engine-house  there  are  two  beam  engines,  with  a  small  fly- 
wheel to  each.  These  engines  hnve  been  35  years  in  use. 

The  two  engines  are  of  the  same  pattern.  Steam  cylinder  24  inches  diam- 
eter, stroke  36  inches  ;  pump  barrel  10  inches  diameter,  stroke  36  inches.  The 
pumps  are  double-acting  pumps,  with  solid  pistons,  taking  water  at  top  and  bot- 
tom. One  of  the  engines  was  at  work,  the  other  at  rest.  The  engine  was 
making  20  revolutions  per  minute  ;  when  well  supplied  with  water  it  makes  26 
revolutions.  The  two  engines  cannot  work  together,  except  at  about  high  water, 
when  the  increased  flow  into  the  pump  well  admits  of  it.  Each  engine  is  pro- 
vided with  an  air  chamber. 

A  12-inch  pipe  main,  5,000  feet  in  length,  proceeds  from  the  pumps  to  a 
storage  reservoir,  the  bottom  of  which  is  72  feet  above  the  pump  well.  The 
pipe  main  to  the  reservoir  serves  as  well  for  a  supply  main  to  the  city.  During 
the  day,  therefore,  the  engine  may  be  said  to  be  pumping  into  the  city,  the  reser- 
voir aiding  it  then,  in  this  respect.  During  the  night  hours,  the  engine  pumps  into 
the  reservoir,  replacing  what  had  been  drawn  off  during  the  day,  and  refilling  it. 
The  reservoir  when  full  holds  500,000  gallons,  equal  to  two  and  a  half  days' 
supply.  Mr.  A.  Bates  is  the  Superintendent  of  the  Perth  Works. 


BERLIN    WATER    WORKS.  HI 


BERLIN    WATER    WORKS. 


PRUSSIA,  May  17, 18G6. 

The  supply  of  water  for  the  city  of  Berlin  is  derived  at  present  mainly  from 
the  river  Spree,  a  tributary  of  the  Elbe,  which  flows  through  the  centre  of  the 
city.  The  Spree  has  its  sources  on  the  slopes  of  the  northern  and  western  spurs 
of  the  Iser  Riessen  hills,  where  numerous  small  lakes  store  up  the  surface  water?, 
and  must  to  some  extent  regulate  the  flow  of  the  river.  The  works  for  the 
transmission  of  the  waters  from  the  Spree  are  situated  above  the  city,  just  out- 
side of  the  walls,  on  the  right  bank  of  the  river.  They  were  executed  in  1854-5 
by  a  private  company,  and  the  delivery  of  the  water  to  the  city  from  this  source 
commenced  in  1856.  The  place  was  previously  supplied  principally  from 
numerous  wells  scattered  all  over  the  city.  Many  of  these  are  still  in  use.  The 
new  works,  -however,  which  give  a  constant  supply  under  pressure  all  over  the 
city,  admitting  of  the  water  being  delivered  into  the  highest  stories  of  the  houses, 
have  already  largely  displaced  the  old  mode  of  supply. 

The  city  possesses  as  yet  no  general  system  of  sewerage,  and  from  the 
numerous  cesspools  which  at  present  exist,  more  or  less  leakage  must  escape  and 
contaminate  the  waters  of  the  wells.  At  present  there  are  no  public  fountains 
(other  than  the  well  pumps)  whence  the  poor,  as  in  most  continental  cities,  can 
obtain  water  free. 

The  works  referred  to  consist  of  8  pumping  engines,  a  system  of  filtering 
works,  and  a  small  storage  reservoir,  situated  on  a  hillock  to  the  north-west, 
about  02  miles  from  the  pumping  station,  and  about  one  mile  outside  of  the  city 
wall.  The  pumping  engines  are  in  pairs,  each  pair  being  connected  with  a  fly- 
wheel. They  are  double-acting  beam  engines,  each  engine  working  two  pump?. 
In  the  four  pumping  engines  first  constructed  the  two  pumps  referred  to  are  of 
unequal  diameter  and  of  unequal  stroke,  the  diameter  of  the  pump  barrels 
being  respectively  38  and  21 3  inches,  the  stroke  32  and  36  inches.  The  large 
barrel  is  used  for  the  delivery  of  the  river  water  to  the  filter  beds,  and  their  con- 
necting basin,  under  a  pressure  not  exceeding  20  feet  ;  the  small  barrel  was  used 
for  the  delivery  of  the  filtered  water  into  the  city  under  a  varying  pressure  of  90 
to  120  feet,  averaging  during  the  day  by  the  gauge  110  feet. 

In  the  four  pumping  engines  last  constructed,  the  two  pumps  to  each 
engine  are  of  equal  diameter  and  equal  stroke,  viz.,  24<z  inches  diameter  and  36 


112  BERLIN   WATER    WORKS. 

inches  stroke.  These  last  engines  are  at  present  used  solely  for  the  high  service, 
the  first  engines  being  now  confined  to  the  low  service  and  worked  with  the 
small  or  high  service  pump  disconnected.  .They  are  in  a  condition,  however,  to 
be  used  as  before,  if  required.  The  pumps  are  all  double-acting  plunger  and 
bucket  pumps.  The  boiler-house  contains  twelve  boilers  of  the  Cornish  pattern. 
The  length  of  each  boiler  is  30  feet,  the  diameter  of  the  shell  58  inches,  and  the 
diameter  of  the  flue  30  inches. 

The  amount  of  water  delivered  from  these  works  into  the  city  was  stated 
to  average  750,000  cubic  feet  per  diem,  equal  to  5,610,400  U.  S.  gallons. 

The  population  of  Berlin  was  given  in  1863  as  455,000.  It  is  supposed  to 
exceed  500,000  now.  If  we  take  but  300,000  as  deriving  their  supply  of  water 
directly  or  indirectly  from  these  works,  it  gives  a  rate  per  head  per  diem  of 
about  19  U.  S.  gallons,  a  .very  low  rate  for  a  city  of  this  character.  It  was  stated 
to  me,  however,  at  the  office  of  the  Water  Works,  that  for  that  portion  of 
the  population  actually  paying  for  the  water,  the  rate  per  head  averaged  22 
imperial  gallons  throughout  the  year,  much  exceeding  this  rate  in  the  hottest 
summer  months. 

The  want  of  a  system  of  sewerage  must  discourage  the  free  use  of  the 
water,  and  the  floating  baths  in  the  river  must  to  some  extent  take  the 
place  of  house  baths. 

The  pumping  engines  work  directly  into  the  city  mains,  but  the  small 
reservoir  already  mentioned,  and  the  stand-pipe  alongside  of  it,  operate  to 
control  and  regulate  the  pressure  upon  the  city.  The  stand-pipe  is  double- 
legged,  and  the  legs  are  connected  at  four  points,  each  connection,  except  the 
highest,  being  controlled  by  a  stopcock.  The  highest  connection  is  200  feet 
above  the  pump  well  of  the  engine-house,  the  lowest  about  115,  and  the  others 
intermediate.  The  water  of  the  small  reservoir,  when  full,  stands  at  about  110 
feet  above  the  pump  well.  The  highest  connection  does  not  seem  to  be  used. 
The  water,  and  therefore  the  pressure,  cannot  rise  above  the  connection  which 
happens  to  be  open,  as  the  overflow  escapes  thus  by  the  down  leg  into  the 
reservoir.  When  that  is  full  the  pumps  are  stopped,  and  the  reservoir  is  left  to 
supply  the  city.  (See  sketch  of  stand-pipe  on  Plate  XVIII.) 

The  capacity  of  the  reservoir  does  not  exceed  one-third  of  the  daily  supply  ; 
it  is,  under  the  ordinary  working  of  the  engine,  filled  every  day,  and  meets  four 
to  five  hours  of  the  night  consumption,  allowing  the  pumping  engines  this  extent 
of  intermission  from  constant  work. 

The  surface  of  this  great  city  is  remarkably  regular  in  plane,  the  difference 
in  the  level  of  any  one  point  from  another,  as  we  were  informed  by  the 
Engineer,  not  exceeding  15  feet. 

The  filter  w.orks,  as  originally  arranged,  comprised  one  settling  basin,  four 
filter  beds,  and  one  open  basin  for  the  reception  of  the  filtered  water.  As  now 


BERLIN    WATER   WORKS.  113 

applied,  the  settling  basin  A  on  the  accompanying  sketch  is  not  considered 
necessary  as  such  ;  it  is  nevertheless  kept  full,  and  form*  a  reserve  of  river 
water,  permitting  the  filter  beds  (to  the  extent  of  the  capacity  of  the  clear-water 
basins)  to  operate  and  deliver  when  the  pumps  are  at  rest. 

There  are  now  six  filter  beds,  the  original  clear-water  basin  having  been 
formed  into  two  filter  beds.  These  are  marked  B  1,  B  2,  B  3,  B  4,  B  5,  and 
B  6.  A  new  and  small  clear-water  basin,  arched  over,  has  been  built  between 
the  filter  beds  and  the  pump-house  (C),  forming  the  clear-water  well  of  the 
high  service  engines.  This  small  basin  has  a  capacity,  I  judge,  of  about  one 
million  U.  S.  gallons. 

The  entire  area  of  the  filter  beds,  by  my  calculation,  comprises  211,600 
square  feet,  but  as  there  are  but  four  in  operation  at  once,  the  area  in  use  does 
not  exceed  145,400  square  feet. 

All  the  water  delivered  to  the  city  passes  through  the  filter  beds  ;  at  the 
rate  of  delivery  given  above,  of  750,000  cubic  feet  in  24  hours,  the  flow 
through  the  filter  beds  is  equal  to  39  U.  S.  gallons  nearly  per  square  foot  of 
their  surface  per  diem.  As  the  clear-water  basin  is  not  large  enough  to  secure 
a  continuous  flow  when  the  pumps  are  not  at  work,  its  capacity  not  being  equal 
to  one-third  of  the  capacity  of  the  reserve  basin  A,  the  actual  movement  through 
the  filter  beds  during  the  day  hours  probably  reaches  75  gallons,  and  in  the  hot 
summer  months  must  exceed  100.  New  filter  beds  are  about  being  constructed, 
and  I  understood  the  Engineer  to  say  that  the  existing  ones  were  sometimes 
taxed  to  a  rate  of  more  than  2  cubic  foot  per  square  foot  per  hour  (equal  to 
891  U.  S.  gallons  per  square  foot  per  24  hours),  a  limit  which,  in  his  opinion, 
should  never  be  exceeded. 

Of  the  two  filter  beds  which  I  have  considered  as  in  disuse  (except  in 
winter),  the  one  was  being  cleansed,  and  the  other  was  being  drained  of  its 
water  preparatory  to  undergoing  the  cleansing  process  ;  this  process  consists  in 
the  removal  of  a  thin  layer  of  the  surface  sand,  which,  after  being  thoroughly 
washed,  is  replaced  and  used  over  again. 

The  refilling  of  an  empty  filter  bed  with  water,  which  in  all  cases  is  an  ope- 
ration of  some  delicacy,  is  effected  here  by  filling  it  from  below.  An  air  pipe, 
connected  with  each  central  drain,  helps  to  relieve  it  from  air.  The  filling  from 
below  is  the  safest  for  the  filter  bed,  if  filtered  water  is  used  for  this  purpose. 
The  filtering  materials  here  consist  of  sand,  gravel,  and  small  boulder  stones. 
These  small  stones,  which  lie  on  the  bottom  of  the  filter  bed,  serve  the  purpose  of 
permitting  the  water  to  reach  a  small  culvert  placed  along  the  centre  line  of 
the  filter  bed,  which  collects  and  conveys  the  filtered  water  to  the  proper  pipe 
outside,  by  which  it  is  carried  to  the  clear-water  basin.  There  are  no  perforated 
pipes  in  the  bottom  of  these  filters  to  perform  this  duty.  A  layer  of  coarse 
gravel  lies  over  the  stones,  and  prevents  the  sand  from  reaching  and  filling  up 


114  BERLIN    WATER   WORKS. 

their  interstices.  The  sand  is  3  feet  in  thickness,  consisting  of  a  layer  of  coarse 
sand,  6  inches  thick,  »over  the  gravel ;  a  layer  of  less  coarse  sand,  12  inches 
thick,  over  this  last,  and  the  surface  layer  of  fine  sand,  18  inches  thick.  I  was 
unable  to  ascertain  the  separate  thicknesses  of  the  .gravel  and  small  stones,  but 
the  entire  filtering  material  is  stated  to  be  58  inches  in  depth.  The  depth  of 
water  over  the  filter  beds  is  from  4i  to  5  feet.  During  certain  months  of  sum- 
mer the  entire  filtering  surface  is  cleansed  once  a  week,  the  separate  beds  being 
taken  in  rotation,  day  by  day. 

When  the  low  service  pumps  are  in  action,  the  river  water  is  pumped 
directly  upon  the  filter  beds,  without  any  previous  process  of  settlement.  The 
water  does  not  carry,  it  is  said,  sufficient  sediment'  to  render  such  a  process 
necessary  in  this  locality.  The  stream  is  very  sluggish  in  its  velocity,  being 
held  back  by  locks  for  the  purpose  of  navigation. 

There  are,  besides,  certain  small  lakes  on  its  course,  not  far  above  the 
works,  through  which  its  waters  flow  before  reaching  the  city.  For  these  causes 
the  stream,  for  miles  above  the  city,  becomes  an  effective  settling  reservoir, 
where  everything  like  palpable  sediment  subsides,  except  in  extreme  cases, 
before  reaching  the  locality  of  the  pumping  works.  The  shallow  ponds  and 
lakes  referred  to  communicate  to  the  water  a  dark  vegetable  tinge.  The  water 
of  the  river  opposite  to  the  filter  beds  is  clearer  than  the  Mississippi  water  of 
midsummer,  after  it  has  undergone  36  hours  settlement.  The  filtering  process 
clarifies  the  water  from  the  faint  sedimentary  tinge,  which  still  remains,  and 
also  separates  from  it  considerable  vegetable  impurity,  which  in  summer  is 
carried  along  with  it. 

The  long  and  severe  winters  here  made  especial  care  and  precaution  neces- 
sary in  the  use  of  filters  during  the  months  of  severe  frost.  The  filter  beds  can- 
not be  laid  bare  in  midwinter,  for  the  frost  would  in  that  case  penetrate  the 
body  of  the  filter  and  render  it  useless.  All  the  filters  are,  in  consequence, 
during  the  winter  months,  kept  constantly  covered  with  their  maximum  depth 
of  water,  four  feet.  Luckily  the  river  water  during  the  winter  months  is  in  its 
best  state  as  regards  freedom  from  turbidity,  and  also  as  regards  freedom  from 
vegetable  discoloration  or  impurity.  The  filters,  therefore,  have,  comparatively 
little  to  intercept,  and,  the  river  water  is  flowed  continuously  upon  them,  and 
passes  through  them  without  very  sensibly  impairing  their  efficiency.  To  make 
provision,  however,  for  an  unusually  long  winter,  or  for  an  exceptional  condi- 
tion of  the  river  then,  which  may  occasionally  occur,  it  is  evident  that  a  larger 
filtering  surface  is  desirable  than  would  be  necessary  in  a  milder  climate. 

The  ice  forms  upon  the  filter  beds  15  inches  thick,  and  sometimes, 
though  rarely,  24  inches  thick.  To  protect  the  enclosing  walls  of  each  filter 
from  damage,  the  ice  is  kept  separated  from  the  walls,  6  to  12  inches,  by 
attendants  appointed  to  that  duty,  and  so  long  as  the  cake  of  ice  is  kept  float- 


BERLIN   WATER   WORKS.  115 

ing  in  this  wa}r,  the  masonry  is  safe  from  any  damage  by  its  thrust.  That  this 
service  has  been  well  performed  is  demonstrated  by  the  condition  of  the  walls 
which  are  in  the  best  of  order,  and  no  where  out  of  line,  or  abraded,  that 
I  could  perceive. 

The  containing  walls  are  nearly  vertical  on  their  faces,  and  it  is  evident 
that  for  such  a  climate  vertical  walls  must  be  more  convenient  as  regards 
ice,  than  the  slope  walls  which  usually  have  place  in  such  works.  The  protec- 
tion of  the  filter  beds  from  the  severe  frosts  of  a  northern  climate  seems  in  this 
case  to  have  been  very  efficiently  managed. 

Cast-iron  pipes  deliver  the  water  upon  the  filters,  one  branch  to  -each  filter, 
controlled  by  a  stopcock. 

The  present  Engineer  and  Manager  of  the  works  is  Mr.  Henry  Grill,  to  whom 
I  am  indebted  for  access  to  the  works,  and  for  much  courtesy  in  affording  me 
such  information  as  I  sought  to  obtain.  As  a  commercial  enterprise  the  works 
have  proved  very  successful. 


UNIVERSITY  OF  CALIFORNIA 

OttPARTMENT  OF  CIVIL  ENGINEERJN9 

BERKELEY.  CALIFORNIA 


116  HAMBURG    WATER   WORKS. 


HAMBURG  WATEPx  WORKS, 


HAMBURG,  May,  1SGG. 
SETTLING  RESERVOIRS— NO  FILTRATION. 

The  water  supply  of  Hamburg  is  derived  from  the  river  Elbe.  The  city  is 
situated  on  the  right  bank  of  the  river,  about  50  miles  from  the  sea.  The  popu- 
lation was  given  me  as  200,000.  In  1860  the  population  of  the  city  proper  was 
134,022,  and  of  its  faubourgs,  44,661,  or  for  both,  178,683. 

The  sources  of  the  "Elbe  lie  principally  on  the  northern  slopes  of  the  Bohmer 
Wald  hills,  but  the  southern  slopes  of  the  Brz  hills  and  of  the  Iser  Riessen  hills 
also  shed  their  waters  into  the  Elbe. 

These  groups  enclose  the  basin  in  the  centre  of  which  lies  the  city  of 
Prague.  '  From  this  upland  region  the  river  flows  towards  the  sea  through  an 
immense  alluvial  plain,  richly  cultivated.  At  Hamburg  the  river  is  but  slightly 
turbid,  except  when  it  comes  down  in  flood.  It  is,  however,  as  seen  in  mass, 
dark  and  cloudy,  even  when  not  in  flood,  and  passing,  as  it  does,  for  the  larger 
part  of  its  course,  through  the  rich  agricultural  region  of  country  alluded  to,  it 
gathers  besides  a  certain  amount  of  vegetable  impurity,  which  becomes  palpable 
in  the  settling  basins,  and  prejudices  the  character  of  the  water. 

The  works  for  the  supply  of  Hamburg  with  water  are  situated  on  the  bank 
of  the  Elbe,  about  two  miles  above  the  city.  At  this  place  there  are  three  set- 
•tling  basins,  with  a  fourth  just  about  completed.  These  basins  arc  filled  at  dis- 
cretion from  the  river.  They  are  each  connected  with  the  river  by  a  pipe  or 
conduit,  having  the  necessary  stopcocks  or  sluices  to  shut  off  or  let  on,  and  they 
are  each  connected  by  a  separate  pipe  with  the  pump  well  of  the  pumping 
engines. 

While  one  of  these  basins  is  in  communication  with  the  pump  well  and 
being  drawn  off',  one  of  the  other  two  is  full  and  at  rest,  and  the  third  one  is 
being  filled,  or  also  at  rest,  as  the  filling  process  may  happen  or  not  to  be  com- 
pleted. 

When  these  works  were  finished,  in  1848,  it  was  supposed  that  the  capa- 
cities of  the  basins  would  admit  of  the  water  in  each  remaining  at  rest  7  to  8 
days  before  being  drawn  off,  and  that  during  this  time  it  would  become  clarified, 
by  subsidence,  of  all  the  impurities  held  in  suspension.  The  clarification  may 


HAMBURG  WATER  WORKS.  117 

• 

have  been  comparatively  satisfactory  under  the  early  circumstances  upon  which 
the  works  were  predicated.     It  is  not  so  now,  however. 

The  consumption  of  water  in  the  city  has  increased  rapidly,  while  the  capa- 
cities of  the  settling  basins  have  not  been  increased  in  the  same  proportion. 
The  basins  hold  each  now  from  2  to  2i  days'  suppty,  according  to  the  season  of 
the  year,  and  this  was  acknowledged  to  be  insufficient  to  clarify  the  water  when 
the  river  came  down  in  flood.  When  I  visited  the  works,  in  May,  1866,  the 
river  stood  three  feet  above  its  low  water  zero  ;  the  water  was  not  in  flood,  and, 
though  discolored,  it  carried  but  a  slight  amount  of  sediment  in  suspension. 

The  water  was  improved  by  the  time  allowed  it  for  settlement  in  the  set- 
tling basins,  but  it  was  not  rendered  limpid,  and  a  considerable  amount  of  vege- 
table growth  was  visible  in  the  bottoms  of  the  basins,  and  the  vegetable  froth  of 
the  river  was  gathered  iti  knots  on  the  surface. 

The  Engineer  of  the  works  informed  me  that  they  would  probably  convert 
part  of  their  space  into  filtering  basins  by  and  by,  instead  of  enlarging  the  ca- 
pacities of  these  basins,  to  render  the  process  of  subsidence  alone  efficient.  The 
Engineer  who  designed  these  works  had  in  view  their  availability  for  such  a  con- 
tingency, as  the  growth  of  the  city  and  further  experience  might  indicate  its 
advisability. 

The  depth  of  water  in  these  basins  averages  12  feet.  Their  arrangement 
will  be  understood  by  an  inspection  of  the  accompanying  sketch.  (Plate  XIX.) 

The  superficies  of  each  basin  was  given  me  as  equal  to  220,000  square  feet. 
My  own  measurements  agree  with  this  statement.  The  capacity  of  each,  accord- 
ing to  my  calculations,  is  about  2,400,000  cubic  feet. 

The  basins  are  of  very  cheap  construction.  It  was  not,  indeed,  necessary, 
in  this  connection,  that  they  should  be  strictly  water-tight.  Their  water  lines 
are  not  provided  with  walls,  as  at  Berlin  and  Altona,  but  rest  on  flat  slopes  of  2 
to  1,  defended  from  the  action  of  the  water  by  loose  stones.  The  water  of  the 
Elbe  being  comparatively  clear  in  midwinter,  the  basins  are  probably  kept  full 
then,  without  being  drawn  down  alternately,  as  in  summer.  The  ice  would 
otherwise  prove  very  troublesome  on  these  flat  slopes.  These  basins  are  cleaned 
out  twice  a  year. 

The  consumption  of  the  city  in  1864  was  396,552,680  cubic  feet — equal  to 
1,086,445  cubic  feet  Hamburg  per  diem,  which  is  equivalent  to  905,371  cubic 
feet  English,  equal  to  6,772,667  U.  S.  gallons  per  diem.  If  the  population  is 
taken  at  200,000,  this  would  give  a  delivery  of  34  U.  S.  gallons  nearly  per  head 
per  diem. 

The  pipe  distribution  of  the  city  is  divided  into  a  high  and  a  low  service. 
The  low  service  is  constant,  and  includes  the  mass  of  the  city.  The  high  ser- 
vice is  intermittent,  the  water  being  delivered  for  that  service  between  the  hours 
of  12  P.  M.  (midnight),  and  5  A.  M.  only.  The  buildings  which  receive  this 

15 


118  HAMBURG   WATER   WORKS. 

high  service  are,  therefore,  provided  with  cisterns,  which  are  filled  during  the 
hours  mentioned. 

There  are  three  Cornish  pumping  engines  at  the  works.  The  engine-house 
is  marked  a  on  the  sketch. 

The  engines  are  beam  engines,  and  have  each  two  plunger  pumps. 

The  two  engines  first  built  have  each  the  same  dimensions.  The  steam 
cylinder  has  an  interior  diameter  of  48  inches,  with  8  feet  stroke. 

The  pump  nearest  the  beam  centre  is  of  20  inches  diameter,  and  5  feet  6 
inches  stroke  ;  the  other  16=1  inches  diameter,  and  8  feet  stroke. 

The  third  engine  has  a  steam  cylinder  of  70  inches  diameter  and  10  feet 
stroke  ;  the  near  pump  is  28  inches  diameter  and  7  feet  6  inches  stroke  ;  the 
other  of  24  inches  diameter  and  10  feet  stroke. 

A  fourth  engine  is  now  being  built,  the  engine-house  for  which  is  being 
constructed  at  b  on  the  sketch.  In  this  engine  the  steam  cylinder"  will  have  85 
inches  diameter,  with  11  feet  stroke,  the  near  pump  to  have  28  inches  diameter 
and  8  feet  stroke,  and  the  other  pump  34  inches  diameter  and  11  feet  stroke. 

The  three  engines  now  in  use  works  into  a  stand-pipe,  as  will  the  last-men- 
tioned when  finished.  The  stand-pipe  has  two  legs  and  two  connections  of  these 
legs  at  different  altitudes.  The  position  of  the  lower  connection  is  120  feet 
above  the  pump  well,  that  of  the  upper  connection  212  feet.  The  brick  tower 
which  protects  and  sustains  the  stand-pipes  is  240  feet  in  height,  and  35  feet 
diameter  at  the  base.  A  brick  chimney,  of  5  feet  interior  diameter,  occupies 
the  centre  of  the  tower,  and  is  connected  with  the  boiler-house.  The  stand- 
pipes  rise  on  either  side  of  the  chimney,  and  are  of  30  inches  diameter  up  to  the 
connection  for  the  lower  service,  and  20  inches  diameter  above  that  point. 

During  all  but  the  few  hours  beyond  niidnight,  the  lower  connection  is 
open,  and  the  engines  work  each  both  of  their  pumps  against  that  head,  satisfy- 
ing then  the  lower  service  of  the  city. 

During  the  hours  from  midnight  to  5  A.  M.,  the  lower  connection  in  the 
stand  pipe  is  closed,  and  the  engines  work  each  one  pump  against  the  high  ser- 
vice head  of  212  feet.  The  other  pump  is  then  working  in  air,  and  not  thrown 
out  of  gear.  This  arrangement  meets  the  requirements  of  the  two  heads  very 
satisfactorily.  The  engines  were  in  excellent  order  and  evidently  well  cared 
for.  They  were  stated  to  work  each  23  hours  daily,  all  the  three  being  required 
to  meet  the  demands  of  the  city. 

There  are  other  two  engines  belonging  to  the  city,  situated  upon  the  river 
bank,  within  the  city  limits.  These  belonged  originally  to  some  other  works. 
They  are  now  held  in  reserve  to  meet  the  contingencies  of  the  excessive  con- 
sumption of  water  which  occasionally  occurs  in  midsummer,  as  well  as  the  con- 
tingencies of  any  extraordinary  repairs  being  required  upon  either  of  the  engines 
above  mentioned.  These  reserve  engines  have  no  settling  basins  connected  with 


HAMBURG  WATER  WORKS.  119 

them,  and  when  in  use  pump  the  water  into  the  city  mains  directly  from  the 
river. 

To  meet  the  requirements  of  the  low  service  for  the  city  during  the  five 
hours  when  the  engines  are  pumping  for  the  high  service,  there  are  three  small 
reservoirs  provided,  situated  at  different  points  within  the  city,  and  each  at 
about  100  feet  in  height  above  the  pump  well.  These  are  each  arched  over, 
and  covered  with  earth,  and  contain  respectively — 

100,000  cubic  feet. 
100,000     " 
400,000     " 


600,000  cubic  feet. 

The  whole  when  full  containing  600,000  cubic  feet,  or  about  two-thirds  of  a  day's 
supply. 

These  reservoirs  are  filled  daily  during  the  working  hours  of  the  pumps  for 
the  low  service. 

The  Hamburg  Works  were  constructed  after  the  designs  and  under  the 
direction  of  Mr.  J.  Lindley,  Civil  Engineer.  They  commenced  the  delivery  of 
water  in  1849,  and  have  been  in  successful  operation  since  that  date. 

I  desire  to  express  my  obligations  to  Mon.  A.  Lienau,  the  Engineer  in 
charge,  for  the  facilities  and  information  afforded  me. 


120  ALTCNA   WATER   WORKS. 


ALTONA  WATER  WORKS, 


ALTONA,  May,  1866. 

The  smaller  city  of  Altona  lies  immediately  below  the  city  of  Hamburg,  and 
on  the  same  bank  of  the  river  Elbe.  The  population  in  1866  was  given  me  as 
numbering  52,000,  in  1860  it  was  45,000.  It  is  a  thriving  and  prosperous  city, 
evidently  growing  rapidly. 

Before  the  construction  of  the  works  which  now  supply  the  city  with  water, 
the  inhabitants  depended  mainly  upon  wells  within  the  city,  many  of  which  are 
still  used  by  them. 

The  new  works  were  constructed  by  a  private  company,  which  still  retains 
the  management  and  control  of  them.  The  plans  were  prepared  by  Mr.  T. 
Hawksley,  Civil  Engineer,  of  London.  They  were  completed  in  1860,  and  have 
proved  very  satisfactory  to  the  inhabitants,  and,  as  I  was  informed,  remunerative 
to  the  Company. 

The  works  comprise  as  follows  :  An  engine-house  and  two  pumping  engines, 
situated  on  the  river  bank,  about  eight  miles  below  the  city  ;  a  system  of  set- 
tling basins  and  filter  basins,  situated  on  the  high  grounds  to  the  north  of  the 
engine-house  ;  a  small  reservoir  within  the  city  of  Altona  ;  and  the  pipe  mains 
which  connect  these  with  each  other  and  with  the  city. 

There  are  two  engines  in  the  engine-house,  each  of  the  same  plan  and 
dimensions.  The  engines  are  double-cylinder  engines,  each  with  crank  and  fly- 
wheel attached,  and  each  working  a  plunger  and  bucket  pump.  They  are  not 
arranged  to  work  in  connection.  The  steam  cylinders  are  respectively  of  35 
inches  diameter,  with  7  feet  stroke,  and  of  20  inches  diameter,  with  5  feet  3 
inches  stroke.  The  engines  work  very  uniformly  an  average  of  16i  strokes  per 
minute.  The  pump  is  a  plunger  and  bucket  pump,  the  barrel  21  inches  diame- 
ter, and  the  plunger  15  inches  diameter,  the  stroke  3  feet  6  inches. 

The  altitude  of  the  full  water  of  the  settling  basins  above  the  pump  well, 
at  low  water  above  the  Elbe,  is  280  feet.  The  rising  main  connecting  the  pump 
with  these  basins  is  18  inches  diameter,  and  about  2,250  feet  in  length. 

The  work  of  one  engine  is  more  than  sufficient  to  supply  the  city  at  present, 
so  that  there  is  always  one  in  reserve  to  meet  accidents  or  repairs.  The  engines 
work  alternately,  week  and  week.  The  work  of  one  engine  12  hours  a  day  for 
four  days  in  the  week  is  competent  to  the  present  consumption  of  the  city 


ALTONA   WATER   WORKS.  121 

The  water  in  the  settling  basins  and  upon  the  filter  beds  forms  the  real  reserve 
to  meet  the  consumption  of  the  remaining  two  days,  the  small  reservoir  in  the 
city  being  of  little  account  in  this  respect ;  during  the  winter  months,  as  the 
water  upon  the  filter  beds  cannot  then  be  drawn  down,  the  reserve  is  reduced  to 
the  water  of  the  settling  basins. 

The  engine-house  and  engines  were  in  excellent  order,  everything  being 
neat  and  clean,  and  well  cared  for.  The  settling  basins  and  filter  beds,  as  already 
mentioned,  stand  on  high  ground,  280  feet  above  the  pump  well. 

The  water  of  the  Elbe  does  not  seem  to  carry  enough  of  sediment  in 
suspension  to  damage  the  pump  valves  rapidly,  and  under  such  circum- 
stances, and  the  ground  being  exceedingly  convenient  for  the  purpose,  the  works 
are  simplified  by  having  but  one  lift  for  the  pumps  instead  of  two,  as  would  have 
been  the  case  had  the  clearing  works  been  placed  contiguous  to  the  river,  and  a 
separate  reservoir  constructed  on  the  high  ground.  The  settling  basins  are  two 
in  number  ;  between  them  there  is  a  smaller  basin  and  two  strainers,  so  called. 
An  examination  of  the  accompanying  sketch  (Plate  XX.)  will  show  their  positions 
The  pipe  main  from  the  engine-house  discharges  into  the  small  basin  a ;  thence, 
the  water  overflows  into  the  strainers  b  fr,  and  from  the  strainers  finds  its  way 
into  the  settling  basins  c  c/,  through  holes  left  for  that  purpose  in  the  intervening 
wall.  The  strainers  were  originally  filled  with  small  stones  and  gravel,  but  the 
difficulty  experienced  in  cleansing  and  keeping  open  this  mixture  has  led  to  its 
removal,  and  the  strainers  are  now  only  filled  in  part  with  stones,  without  admix- 
ture of  gravel. 

The  settling  basins  are  cleaned  out  twice  a  year,  which  of  itself  shows  that 
the  amount  of  sediment  carried  down  by  the  river,  although  sufficient  to  discolor 
the  water,  is  small  in  body  except  during  heavy  floods.  I  could  not  learn  that 
the  depth  of  mud  in  the  settling  basins,  when  cleaned  out,  exceeded  15  inches, 
but  in  the  small  basin  (a)  the  mud  accumulates  much  more  rapidly  than  in  the 
settling  basins.  The  settling  basins  are  each  138  feet  long  by  66  feet  wide,  and 
they  contain  11  faet  in  depth  of  water,  though  not  more  than  10  feet  of  that 
water  is  ever  drawn  off.  The  side  walls  are  of  brick,  and  nearly  vertical.  The 
contents  of  each  of  these  basins  at  10  feet  of  water  is  about  91,000  cubic  feet,  or 
for  both,  182,000  cubic  feet.  The  average  consumption  of  the  city  being  at  pres- 
ent 80,000  cubic  feet  per  diem,  this  is  equal  to  2i  days'  reserve.  If  we  add  to 
this  the  water  upon  the  filter  beds  and  in  the  clear-water  reservoir  at  present, 
it  would  reach  to  five  days'  supply. 

There  are  four  filter  beds  (d\  d\  ds,  d*)  each  136  feet  long  by  66  feet 
wide.  The  depth  of  water  upon  the  filters  is  four  feet ;  their  surface  waters, 
when  full,  are  on  a  level  with  the  bottom  of  the  settling  basins. 

The  filtering  materials  are  principally  sand  and  gravel,  arranged  as  follows  : 


122  ALTON  A   WATER   WORKS. 


Fine  screened  sharp  sand  

IT. 

3 

IN. 

0 

Fine  gravel  .... 

0 

fi 

Gravel  of  size  of  hazel  nut  

0 

3 

Gravel  of  size  of  walnut  

.    ..   0 

6 

Large  pebble  stones  3  to  4  inches  diameter  .... 

0 

9 

Small  gathering  drains  and  large  stones  

5 
1 

0 

n 

Total  . 

6 

0 

At  my  visit  (May,  1866)  three  of  the  niters  were  covered  with  water  and 
one  was  being  cleansed.  The  cleansing  of  one  filter  in  three  weeks  is  sufficient 
at  this  season  of  the  year.  When  heavy  floods  prevail,  one  filter  cleansed  per 
week  is  still  sufficient.  Here,  as  in  Berlin,  the  filter  beds  are  quite  as  useful 
for  separating  from  the  water  all  vegetable  impurities  as  for  its  clarification, 
and  they  intercept  as  well  fish  of  every  description. 

The  superficial  area  of  the  four  filters  amounts  to  36,432  square  feet. 
Assuming  three  of  the  above  filter  beds  to  be  constantly  serviceable,  this  would 
give  a  filtering  capacity  of  27,324  cubic  feet,  equal  to  2,869,105  U.  S.  gallons 
per  diem. 

The  average  daily  consumption  of  water  now,  being  80,000  cubic  feet,  or 
598,440  U.  S.  gallons,  the  filter  surface  is  sufficient  to  meet  four  times  the 
present  rate  of  supply.  A  considerable  portion  of  the  population,  however, 
still  draws  from  the  old  wells  ;  but  as  the  number  using  the  new  works  is  rapidly 
augmenting,  and  the  city  growing  rapidly,  the  anomaly  of  an  over-abundant 
provision  will  not  long  continue. 

The  present  rate  of  filtration,  with  three  filters  in  use,  averages  but  19 
imperial  gallons  (23!  U.  S.  gallons)  per  square  foot  per  diem. 

The  filters  discharge  into  a  clear-water  basin  (C),  which  is  arched  over  and 
covered  with  earth.  This  last  has  a  capacity  of  109,500  cubic  feet,  equal  to 
819,116  U.  S.  gallons. 

The  amount  of  sand  removed  from  the  surface  of  a  filter  bed  in  cleansing, 
the  attendant  described  to  me  as  about  half  an  inch  in  thickness,  or  as  thin  a 
layer  as  can  practically  be  removed. 

This  sand  is  not  cleansed  and  used  over  again  here,  but  it  is  replaced  by  a 
thin  layer  of  fresh  sand. 

Upon  the  settling  basins  and  filter  basins,  the  ice  in  winter  forms  to  the 
depth  of  15  to  20  inches.  The  walls  in  all  these  basins  are  vertical.  The  ice  is 
not  allowed  to  form  close  up  to  the  walls,  but  a  space  of  from  18  inches  to  24 
inches  is  kept  clear  all  round  in  all  the  basins.  In  this  way  they  find  it  easy  to 


ALTON  A   WATER   WORKS.  123 

protect  the  walling  from  any  damage  by  ice.  The  walls  were  all  in  line  and  in 
good  order.  During  the  winter  months,  the  filter  beds  are  all  kept  covered  with 
water,  and  are  not  then  laid  bare  for  the  purpose  of  cleansing.  Luckily,  the 
river  water  then  is  usually  in  its  best  state,  and  the  filters  do  not  get  choked 
during  the  long  interval.  It  is  evident,  however,  that  for  such  climates  a  larger 
filtering  space  should  be  provided  than  in  situations  where  the  formation  of  ice 
does  not  take  place. 

From  the  clear-water  basin  to  the  city  the  pipe  main  is  about  7  miles  in 
length,  and  of  16  and  15  inches  in  diameter. 

Two  large  villages  on  the  route  are  supplied  with  the  same  water.  It  was 
stated  to  me  that  the  population  supplied  at  this  date  did  not  probably  exceed 
30,000,  which  would  give  a  rate  of  20  U.  S.  gallons  per  head  nearly. 

The  small  reservoir  alluded  to  as  situated  within  the  city  was  built,  in  some 
measure,  to  meet  the  contingency  of  a  break  in  the  pipe  main  between  the 
works  and  Altona,  to  provide  water  during  the  time  of  its  repair.  It  is  situated 
on  the  highest  ground  of  the  city,  and  raised  some  30  feet  above  the  street.  It 
has  a  capacity  of  16,000  cubic  feet,  which  is  equal  to  about  120,000  U.  S. 
gallons. 

For  much  of  the  information  obtained  during  my  visit  to  these  works  I  am 
indebted  to  the  Engineer  in  charge  of  the  works,  Mons.  H.  Salzenburg. 


124  TOURS   WATER   WORKS. 


TOURS,  OX  THE  LOIRE  RIVER. 


APKIL,  I860. 

The  city  of  Tours  lies  on  the  river  Loire,  but  its  supply  of  water,  with  the 
exception  of  a  small  quantity  got  from  artesian  wells,  is  derived  from  the  river 
Cher,  a  tributary  of  the  Loire.  The  Cher  enters  the  Loire  about  six  miles 
below  the  city,  which  lies  on  the  ground  intervening  between  the  rivers  Loire 
and  Cher,  resting,  however,  directly  upon  the  Loire.  The  Cher  river  has  its 
sources  in  the  granite  slopes  of  the  Auvergne  and  Limousin  mountains,  in  the 
departments  of  Creuse  and  Altier.  The  river  at  Tours,  by  its  passage  through 
the  rich  plains  above,  has  acquired  a  muddy  hue,  and  it  is  only  during  its  very 
low  summer  stages  that  the  water  becomes  comparatively  clear.  Although 
deeply  discolored  when  seen  in  mass,  as  in  the  river,  the  amount  of  sediment 
held  in  suspension,  in  April,  1866,  was  very  small.  The  population  of  the  city 
is  stated  at  42,000. 

The  works  (Rochepinard  usine  hydraulique)  on  the  river  Cher,  for  the 
supply  of  the  city,  consist  of  an  artificial  filter  in  two  divisions,  a  canal  from  the 
river  passing  over  this  double  filter,  and  acting  also  as  a  mill-race  to  two  tur- 
bine wheels  ;  an  engine-house,  containing  eight  pumps,  worked  by  the  two 
turbines,  and  two  extra  pumps  worked  by  an  auxiliary  steam-engine  ;  a  tail- 
race  thence  to  the  river.  These  works,  which  lie  on  the  banks  of  the  stream, 
within  its  dyke,  are  distant  about  2 2  miles  from  the  city  proper. 

The  river  Cher  has  been  long  used  for  what  is  called  slack  water  navigation, 
and  there  existed  a  dam  and  lock  on  the  river  at  this  point  (the  Rochepinarde 
dam),  before  the  construction  of  the  water  works  was  contemplated.  Advan- 
tage was  taken  of  this  dam  to  obtain  water  power  for  operating  the  pumps. 
The  relative  positions  of  the  canal,  the  pump-house,  and  the  tail-race,  are  shown 
on  the  accompanying  sketch  (Plate  XXI.) 

The  water  drawn  from  the  river  to  operate  the  two  turbine  wheels  passes 
over  the  filter  beds.  The  cross  section  of  these  filters  will  show  that  the  surface 
of  the  filter  beds  and  the  bottom  of  the  canal  correspond.  The  central  wall, 
shown  on  the  sketch,  which  divided  the  canal  into  two  mill-races,  separates  the 
one  filter  bed  from  the  other.  The  two  divisions  of  the  canal,  or  the  separate 
mill-races  for  the  two  turbines,  form  as  well  the  two  separate  filter  beds. 


TOURS    WATER    WORKS.  125 

These  filters  are  entirely  artificial,  as  contradistinguished  from  what  are 
called  natural  filters.  They  are  composed  of  4  feet  6  inches  in  depth  of  fine 
sand  and  gravel,  resting  on  a  layer  of  dry  brick,  which  again  rests  on  a  bed  cf 
beton.  The  beton  lies  here  upon  a  calcareous  rock.  A  small  conduit,  about  20 
inches  square,  as  shown  on  the  cross  section,  collects  the  filtered  water  and  con- 
veys it  to  the  pump  well.  The  filtered  water  finds  its  way  into  the  conduit  by 
small  holes  arranged  in  the  bricks  of  its  side  walls  for  this  purpose. 

The  depth  of  water  lying  on  these  filter  beds  is  regulated  by  the  sluice 
gates  above.  There  were  about  4<z  feet  of  water  over  them  on  the  19th  of 
April,  and  this  depth  was,  we  presume,  necessary  then,  to  work  the  turbine 
wheels.  The  head  of  water  on  these  filter  beds  would  depend  on  the  height  of 
the  water  in  the  pump  well.  Upon  this  head,  however  it  may  be  regulated, 
depends  the  velocity  of  the  water  through  the  filtering  material,  an  important 
element  in  the  process  of  filtering. 

The  two  filter  beds  have  a  joint  area  of  9,688  square  feet.  This  area,  at 
90  U.  S.  gallons  per  square  foot,  would  filter  efficiently  871,920  U.  S.  gallons  in 
24  hours  ;  or,  if  we  suppose  but  one  filter  in  operation,  the  other  undergoing 
the  process  of  cleansing,  435,960  U.  S.  gallons  in  24  hours.  But  the  consump- 
tion of  water  in  the  city  averages  about  924,700  U.  S.  gallons  in  24  hours. 

The  filters  are  therefore  too  small  to  furnish  under  all  circumstances  the 
requisite  supply,  although  in  1856,  when  these  works  were  opened,  and  the  pop- 
ulation was  not  so  large,  they  would  have  been  ample,  and  doubtless  satisfac- 
tory, had  the  system  been  in  other  respects  perfect.  But  there  were  no  settling 
reservoirs  provided  to  rid  the  river  water  of  the  heavier  portions  of  its  sediment 
and  prepare  it  for  the  successful  action  of  such  filter  beds.  It  is  well  understood 
now,  that  no  artificial  filter  beds  will  operate  regularly  and  satisfactorily  if  the 
river  water,  as  it  comes  down  in  heavy  floods,  is  thrown  directly  upon  them, 
and  all  the  sediment  then  in  suspension  permitted  to  deposit  itself  upon  the  filter 
bed.  The  surface  sand,  under  these  circumstances,  becomes  speedily  clogged 
and  inoperative. 

The  works  were  opened  in  1856,  and  these  filters,  as  we  are  informed  by 
the  Engineer  in  charge,  have  been  inefficient  from  the  first  season  ;  the  supply 
now  is  drawn  directly  from  the  river. 

These  filters  are  not  arranged,  or  intended  to  be  cleansed  as  in  the  ordinary 
English  practice,  by  laying  them  bare  at  short  intervals,  and  removing  the  thin 
layer  of  sand  upon  which  the  intercepted  sediment  has  accumulated.  The  mode 
of  cleansing  designed  here,  was  by  reversing  the  flow  of  the  water  through  the 
filter,  and  forcing  it  upwards  through  the  filtering  material  under  such  a  head  as 
would  carry  with  it  the  sediment  deposited  by  the  turbid  water  on  the  surface 
of  the  filter  bed. 

To  effect  this  the  river  sluice  gates  of  the  filter  bed  to  be   cleansed  were 

16 


126  TOURS   WATER   WORKS. 

closed.  This  would  cause  the  water  over  the  filter  to  sink  to  about  the  level  of 
the  tail-race.  The  small  conduit  of  this  filter  was  then  put  in  communication 
with  the  water  of  the  other  filter  bed,  the  difference  of  level  varying  with  the 
stage  of  the  river.  Under  the  head  thus  produced  the  water  rose  upwards 
through  the  filter  to  be  cleaned,  in  process  of  time  carrying  more  or  less  of  the 
surface  sediment  with  it. 

The  Engineer  states  that  the  head  of  water  at  command  was  not  sufficient 
to  make  the  process  efficient,  and  that  between  the  averred  difficulty  and  the 
deficiency  in  area  of  the  filter  beds,  or  other  reasons,  they  never,  from  the  begin- 
ning, have  operated  satisfactorily,  and  are  unserviceable  now. 

The  turbine  wheels  work,  each,  four  single-acting  pumps  ;  the  pumps  are 
each  (0.32  m.)  12s  inches  diameter,  and  (0.50  m.)  19s  inches  stroke.  Their 
united  delivery  at  a  velocity  of  16  strokes  per  minute,  which  may  be  taken  as 
their  maximum,  was  stated  to  us  to  be  equal  to  100  litres  (3.53  cubic  feet)  per 
second=S640  cubic  metres,  or  2,282,515  U.  S.  gallons  per  diem,  but  their  ordi- 
nary work,  or  the  average  delivery  of  water  into  the  city,  does  not  evidently 
exceed  (3500  cubic  metres)  924,700  U.  S.  gallons  per  diem. 

This  amount,  for  the  population  of  42,000,  is  equal  to  22  U.  S.gallons  per 
head.  At-  the  time  of  my  last  visit  (21st  of  April,  1866),  one  of  the  turbines 
was  working  three  pumps  at  10  strokes  per  minute,  and  the  other  one  two  pumps 
at  11  strokes  per  minute.  The  river  was  in  flood,  and  the  head  upon  the  tur- 
bines about  Om.  35  (13*  inches). 

The  water  in  the  river  at  its  very  lowest  stage  leaves  the  surface  of  the  filter 
beds  (the  bottom  of  the  canal  or  mill  race)  so  nearly  bare  as  to  render  the  tur- 
bine wheels  inoperative.  At  the  highest  stage  of  the  river  the  turbine  wheels 
become  equally  incompetent  to  the  work  required  of  them.  In  high  floods  the 
darn  is  drowned,  and  the  available  fall  of  the  wheels  is  at  times  reduced  to  4 
inches.  To  meet  these  difficulties,  as  well  as  to  admit  of  the  more  convenient 
maintenance  and  repair  of  the  other  machines,  a  steam-engine  is  provided,  work- 
ing two  pumps  of  Om.  33  (13  inches)  diameter  each,  and  Oin.  40  (15 1  inches) 
stroke.  The  delivery  of  the  steam  pumps  reaches  30  litres  per  second  (2592 
m.  c.)  684,807  U.  S.  gallons  per  diem  (16.3  galls,  per  head  of  the  population). 

The  water  in  the  river,  19th  April,  1866,  was  1.60  metres  (5s  feet)  above 
(1'etiage)  its  lowest  stage.  The  river  was  then  in  flood,  and  although  the  dam 
here  has  a  height  of  (1 .5  metres)  about  5  feet,  and  would  give  that  amount  of 
available  fall  in  moderate  stages  of  the  river,  the  fall  available  at  the  turbines  at 
this  time  was  but  12  inches.  The  highest  flood  on  record,  4th  June,  1856,  rose 
to  (5.90  metres)  19  feet  above  extreme  low  water. 

There  is  but  one  pipe  main  of  11.8  inches  diameter  into  the  city,  but  a 
second  is  to  be  laid  shortly.  There  is  no  receiving  reservoir  of  sufficient  capa- 
city to  relieve  the  pumps  from  constant  service.  One  of  the  machines  requires 


TOURS   WATER   WORKS.  .127 

to  be  constantly  in  operation.  A  small  reservoir,  holding  about  58,000  gallons, 
has  been  placed  in  the  Charlemagne  tower,  and  would  be  of  service  in  a  case  of 
fire,  or  some  very  short  interruption  of  the  supply  ;  but  as  it  can  hold  but  about 
1*  hours  consumption,  it  is  too  small  to  relieve  the  pumps  from  constant  service. 
The  water  in  the  reservoir  stands,  when  full  (22  metres),  72  feet  above  the 
floor  of  the  pump-house,  or  about  82  feet  above  the  water  there  at  this  date. 
The  city  stands  low  and  level,  and  this  head  permits  the  water  to  be  deliv- 
ered into  the  first  and  second  stories  of  such  houses  as  desire  it.  The  inhab- 
itants, however,  draw  the  most  of  their  water,  as  is  usual  in  French  cities, 
from  the  public  fountains,  which  are  numerous  over  the  city. 

The  reservoir,  which  is  an  iron  tank  8  metres  deep,  was  empty  when  I 
visited  it  (23d  April,  1866),  the  head  of  water  on  the  turbines  at  this  time  not 
being  sufficient  to  lift  the  water  as  high  as  the  tank.  Under  such  circumstances 
the  supply  is  limited  to  the  fountains  and  the  lowest  floors  of  buildings.  So  far 
as  I  can  learn,  there  have  been  13  borings  made  in  the  city  to  obtain  water  by 
artesian  wells,  seven  of  which  deliver  water  now  ;  the  others  are  not  in  use.  The 
largest  of  these  belongs  to  a  brewery,  which  uses  the  water  for  brewing  and 
cleansing  casks.  The  larger  portion  of  it,  however,  was  running  to  waste.  Such 
of  the  neighbors  as  fancied  the  water,  supplied  themselves  from  it.  The  water 
was  described  by  the  brewer  as  slightly  sulphurous  and  ferruginous  in  its 
character,  and  that  this  mineral  taint  was  characteristic  of  all  the  artesian  wells 
here.  The  depth  of  this  bore  was  160  metres,  about  500  feet,  and  they  all 
ranged  from  350  to  500  feet.  This  well  was  stated  to  deliver  1,000  litres 
per  minute,  and  so  far  as  I  could  learn,  the  flow  of  all  was  about  2,000 
litres  (528  U.  S.  gallons)  per  minute.  The  flow  from  these  wells  has  varied 
very  much,  and  lessened  very  much,  since  they  were  first  sunk.  Mr.  Darcy 
describes  them  in  his  work  on  the  fountains  of  Dijon,  1856.  Most  of  these 
wells  seem  to  have  been  sunk  for  private  use,  and  much  of  their  water  is 
allowed  to  run  to  waste. 

Mr.  Chavran,  the  Architect  and  Director  of  the  Tours  Works,  was  very 
courteous  and  obliging  in  giving  information  and  permitting  me  to  copy  the 
plan  of  the  filter  basins.  I  am  also  greatly  indebted  to  Mr.  Claude  T.  Roussel, 
the  mechanician  at  the  works,  for  the  facilities  and  assistance  afforded  me 
towards  understanding  them. 


128  ANGERS  WATER  WORKS. 


ANGERS    WATER  WORKS, 


AUGUST,  1866. 
NATURAL   FILTRATION. 

The  city  of  Angers  lies  on  the  river  Maine,  a  tributary  of  the  Loire.  The 
river  Loire  flows  within  three  miles  of  the  city,  and  it  is  from  an  island  in  the 
Loire,  at  the  Fonts  de  Fe,  that  the  city  is  supplied  with  water.  The  Loire  has 
its  sources  in  the  mountains  of  Lazere,  Vivarais,  and  Auvergne  ;  but  its  many 
tributaries  from  calcareous  regions  change  the  character  of  its  original  streams, 
and  render  the  water  at  Angers  and  Nantes  turbid  and  somewhat  hard.  The 
population  in  1863,  was  51,797,  it  may  now  be  taken  at  53,000  ;  but  the  por- 
tion supplied  with  water  from  these  works  does  not  exceed  50,000.  The  works 
are  under  the  immediate  control  of  the  city  authorities.  Upon  the  island  re- 
ferred to,  the  engine-house  is  placed.  It  contains  two  steam  pumps  with  the 
requisite  boilers.  The  well  of  the  pumps  is  connected  with  and  receives  its 
water  from  fiftering  galleries,  situated  as  shown  in  the  accompanying  sketch. 
(Plate  XXII.) 

The  works  have  been  in  operation  ten  years  (since  1856).'  Until  1861,  the 
only  filtering  galleries  were  those  marked  A  and  B,  each  of  about  the  same 
length  and  size.  In  low  stages  of  the  river  the  supply  from  these  galleries  was 
not  sufficient  to  keep  the  one  pumping  engine  at  work  uninterruptedly  ;  but  by 
working  intermittently,  that  is,  by  stopping  the  engine  every  2  or  3  hours,  and 
allowing  the  galleries  to  fill  up,  the  supply  to  the  city  was  generally  maintained. 
During  the  very  low  season,  however,  of  1858,  the  river  fell  so  low  as  to 
render  the  supply  insufficient,  even  when  gathered  intermittently  in  this  way. 
For  upwards  of  30  days  the  amount  thus  obtained  per  diem  ranged  from  1,000 
to  800  cubic  metres,  amounts  mrich  below  what  the  city  required  then.  The 
necessity  for  extending  the  filtering  galleries  was  thus  brought  home  to  all,  and 
the  third  gallery,  C,  was  projected  and  built  in  1861. 

With  this  gallery,  the  Engineer  informed  me  that  they  could  rely  on  a 
delivery  of  (3,000  metres  cubic)  792,600  U.  S.  gallons  at  the  lowest  stage  of  the 
river.  The  average  consumption  now  is  (2,156  metres  cubic)  569,700  U.  S. 
gallons,  which,  for  the  population  of  50,000,  gives  a  rate  per  head  of  about 
1H  U.  S.  gallons. 


ANGERS  WATER  WORKS.  129 

The  materials  of  the  island  in  which  the  filtering  galleries  are  placed,  con- 
sist of  earth,  sand  and  gravel,  resting  on  a  bed  of  argillaceous  marl,  which  is 
impervious  to  water.  The  sand  predominates.  The  bottom  of  the  first  galleries, 
A  and  B,  are  carried  down  to  this  clayey  substratum,  but  the  new  gallery  is 
not  carried  so  low. 

The  clayey  basis  (Talle)  is  found  at  (8  metres)  about  25  feet  below  the  gen- 
eral surface  of  the  island.  The  island  is  covered  with  water  in  high  floods. 

The  bottom  of  the  wide  portion  of  the  first  galleries  (see  the  cross  sections) 
is  (2.90  metres)  9iz  feet  below  (1'etiage)  the  lowest  water  of  the  Loire,  the  bot- 
tom of  the  wings  (2.30  and  2.40  metres)  7i  and  71  feet  below  the  same  line, 
and  the  bottom  of  the  new  gallery  (1.68  metres)  62  feet  below  it. 

The  total  length  of  the  first  galleries,  with  the  two  short  branches,  is  (88 
metres)  288  feet.  If  we  take  the  extreme  low  water  per  diem  of  this  gallery, 
as  given  by  the  Engineer  (800  m.  c.),  211,360  U.  S.  gallons — and  this,  where 
there  are  no  storage  reservoirs  to  collect  surplus  water,  is  the  only  safe  measure 
for  the  city — we  have,  in  this  case,  a  delivery  of  739  U.  S.  gallons  per  lineal 
foot  of  gallery  at  low  water. 

The  total  length  of  the  new  gallery  is  (300  metres)  984  feet.  If  we  take 
the  low  water  capacity  of  the  new  gallery  from  the  same  data  (3,000=808= 
2.200  m.  c.)  at  581,240  U.  S.  gallons,  we  have  a  rate  per  lineal  foot  of  590  U. 
S.  gallons.  The  new  gallery  stretches  towards  the  main  channel  of  the  Loire. 
The  islands  here  divide  the  river  into  three  channels.  The  first  galleries  are 
placed  near  the  smallest  channel,  which  is  all  but  dry  in  very  low  stages  of  the 
river. 

The  first  galleries,  as  will  be  seen  by  the  sketch,  are  open  at  the  side  ;  the 
usual  mode  of  referring  their  capacity  of  delivery  to  the  square  feet  in  the  bot- 
tom is  therefore  hardly  applicable  here.  I  will,  however,  give  the  indications 
by  this  mode. 

The  first  galleries  have  the  following  bottom  widths  and  areas  : 

26  metres  in  length  by  1.66  wide  at  10.76  sq. 

feet  per  sq.  metre= 464  sq.  feet. 

62  m.  length  and  ]  m.  wide= 667 

1131  sq.  feet. 

This  is  equal  to  187  U.  S.  gallons  per  square  foot  of  bottom. 

The  length  of  the  new  gallery  is  300  metres  by  0.60  metres  width  of  bot- 
tom=l,937  square  feet. 

This  gives  a  rate  of  300  U.  S.  gallons  per  square  foot  of  its  bottom. 

The  entire  lengths  of  the  galleries  (1,272  feet)  give  623  U.  S.  gallons  per 
lineal  foot. 


130  ANGERS  WATER  WORKS. 

The  size  and  form  of  the  galleries  will  be  seen  on  the  accompanying  sketch. 
The  old  galleries  rest  upon  a  construction  of  timber  and  cobble  stone,  the  whole 
depending  upon  the  permanence  and  solidity  of  the  timber.  The  body  of  the 
wide  part  of  the  old  galleries  is  10  feet  in  width,  the  rest  of  it  62  feet,  but 
the  bottom  widths  are  but  5?  and  ok  feet  respectively.  The  new  gallery  has  a 
width  of  2  feet. 

When  I  visited  the  galleries  (April  27th,  1866),  the  river  stood  62  feet 
above  low  water,  and  the  water  in  the  filtering  gallery  at  noon,  0.85  metres 
above  the  same  low  water,  or  (1.15  m.)  3i  feet  below  the  river  as  it  flowed  then. 
The  water  of  the  new  gallery  was  not  then  in  communication,  being  cut  off  by 
a  tight  sluice  prepared  for  that  purpose. 

The  old  galleries  supply  an  abundance  of  water  at  the  present  stage  of  the 
river.  The  new  gallery  is  not  needed  at  this  stage  ;  when  the  river  is  in  flood, 
as  now,  its  water  is  discolored,  and  for  that  reason  cut  off.  When  the  river  is 
not  in  flood,  the  new  gallery  is  kept  open,  and  when  it  is  very  low,  the  aid  of 
the  new  gallery  is  indispensable  ;  the  river  water  being  comparatively  clear 
when  low,  the  water  from  the  new  gallery  is  then  clear  and  unobjection- 
able. 

I  was  disappointed  in  the  water  of  the  old  galleries.  Although  clear,  it 
was  not  so  perfectly  so  as  the  water  of  the  same  character  of  galleries  at 'Genoa, 
Toulouse,  and  Lyons.  Here  the  water  was  not  entirely  limpid.  This  would 
show  that  the  galleries  are  on  too  small  a  scale  for  the  material  in  which  they 
are  situated,  and  that  the  draft  into  them  has  a  velocity  sufficient  to  carry  some 
portion  of  sediment  with  it. 

It  may  be  mentioned  here  that,  during  the  great  flood  of  1856,  the  water 
rose  (6.76)  22  feet  above  its  lowest  record.  When  the  river  is  so  high  as  to 
cover  the  island,  the  filtering  galleries  do  not  produce  clear  water. 

The  water  accumulates  in  these  galleries  during  the  night,  when  the  pump- 
ing engine  is  not  at  work ;  and  when  the  engine  begins  work  at  5  A.  M.,  the 
water  stands  in  the  gallery  at  nearly  the  same  level  as  the  water  in  the  river. 
The  water  is  lowered  by  the  pumping  process  about  3z  feet.  During  the  last 
two  or  three  hours  of  the  working  of  the  pumps,  the  water  ceases  to  lower, 
showing  that  the  flow  into  the  gallery  then  equals  the  quantity  withdrawn  by 
the  pumps. 

By  reference  to  the  cross-section  of  the  new  gallery,  it  will  be  seen  that  no 
provision  is  apparent  there  for  the  entrance  into  it  of  the  filtered  water.  The 
bottom  is  composed  of  a  thin  layer  of  beton,  and  the  side  walls  and  arch  are  of 
masonry  ;  the  stones  bedded  in  part  in  hydraulic  cement  mortar. 

The  Engineer  informed  me  that  the  walls  were  thin,  and  the  water  found 
its  way  sufficiently  through  the  joints  of  the  slaty  stones  of  which  it  is  built, 
rendering  special  openings  of  any  kind  unnecessary.  The  backing  of  stones 


ANGERS   WATER   WORKS.  131 

behind  the  walls  prevents  the  sand  from  reaching  the  masonry  and  filling  up 
these  crevices. 

The  delivery  of  a  gallery  of  this  description  cannot  fairly  be  compared  with 
galleries  of  an  entirely  different  character,  as  regards,  the  provisions  for  the 
entry  of  the  water. 

There  arc  two  steam  pumping  engines  at  the  work. 

The  oldest,  which  has  been  in  use  since  1856,  has  a  vertical  steam  cylinder, 
with  fly-wheel  attached.  The  pump  is  directly  under  the  cylinder.  The  pump 
is  a  plunger  and  bucket  pump,  the  plunger  0.40  diameter  (15?  inches),  and  the 
bucket  or  pump  cylinder  0.50  metres  diameter  (19?  inches)  ;  the  stroke  is  (1.25 
metres)  four  feet,  and  the  engine  was  making  18  strokes  per  minute. 

This  engine  has  worked  during  the  month  of  April  very  regularly  an 
average  of  11  hours  per  day,  delivering  in  that  time  2,156  cubic  metres,  against 
a  head  of  water  at  this  time  of  50  metres  (164  feet),  increasing  or  decreasing 
with  the.  variations  in  the  water  of  the  Loire,  which  again  affect  the  position  of 
the  water  in  the  galleries. 

The  second  machine,  which  has  been  built  within  the  last  five  years,  was 
under  repairs,  and  is  not  used  except  in  the  hot  months  of  summer,  when  the 
city  consumption  is  much  increased,  or  when  the  other  machine  is  under  repair. 
It  has  a  horizontal  steam  cylinder,  connected,  like  the  other,  with  a  fly-wheel. 
The  pump  is  vertical ;  it  is  a  plunger  and  bucket  pump,  of  the  same  diameter 
as  the  other,  but  with  a  stroke  of  only  (6.50  metres)  1  foot  8  inches.  This 
engine,  we  are  informed,  made  28  revolutions  per  minute. 

A  pipe  main,  of  (0.35  metre)  13i  inches  diameter,  delivers  the  water 
into  the  city,  where  a  net-work  of  smaller  pipes  distributes  it  through  the 
streets. 

Connected  with  this  pipe  main,  there  are  two  cisterns  or  tanks  in  the  Rue 
de  Madeline  of  300  cubic  metres  each  (T9,354  U.  S.  gallons),  the  water  of  which 
stands  when  full  52  metres  (170  feet)  above  the  pump  well ;  and  one  larger  cis- 
tern, near  the  Champ  de  Mars,  of  2,500  cubic  metres  (660,450  U.  S.  gallons) 
capacity,  the  water  of  which  stands  about  33  metres  (108  feet)  above  the  pump 
well.  The  lower  cistern  is  connected  with  the  lower  part  of  the  city,  and  the 
action  of  the  upper  ones  is  confined  to  the  pipes  of  the  higher  grounds.  The 
overflow  of  the  high  cisterns  supplies  the  lower  one  with  water  by  two  special 
pipe  mains  for  that  duty,  and  the  lower  cistern  has  no  other  connection  with  the 
pumping  engines.  The  pump,  therefore,  is  working  always  under  the  head  of 
water  which  prevails  in  the  high  cisterns,  which  are  soon  filled. 

The  three  cisterns  have  a  joint  capacity  of  819,000  U.  S.  gallons,  and  sup- 
posing them  to  be  but  little  over  two-thirds  full,  they  have  thus  a  reserve  of  one 
day's  supply,  a  reserve  that  is  sufficient  to  relieve  the  pumping  engine  from  con- 
tinuous work,  and  to  admit,  therefore,  of  its  being  easily  kept  in  ordinary  repair. 


132  ANGERS  WATER  WORKS. 

During  extraordinary  repairs,  requiring  some  days  or  weeks  of  intermission, 
the  second  engine  is  in  reserve  to  meet  the  required  supply.  . 

The  head  of  water  available  is  sufficient  to  reach  the  different  stories 
of  all  the  houses  except  those  situated  on  the  highest  grounds,  where  it 
can  only  reach  the  first  story. 

The  public  fountains  are  kept  open  7  hours  a  day — from  6  to  9  A.  M., 
and  from  3  to  7  P.  M. 

The  Engineer  in  charge  of  the  works  very  obligingly  furnished  me  with 
a  sketch  of  the  ground,  and  with  the  details  which  accompany  it,  of  the 
filtering  galleries. 


NANTES    WATER    WORKS.  133 


NANTES  WATER  WORKS, 


NANTES,  April  25,  1866. 

The  city  of  Nantes  is  situated  on  the  right  bank  of  the  river  Loire,  just 
above  tidal  influence.  The  population  at  this  date  is  estimated  at  112,000. 

The  water  for  the  supply  of  the  city  is  obtained  from  the  Loire,  whence  it 
is  pumped  into  three  small  reservoirs,  situated  (40  metres)  131  feet  above  ordi- 
nary water  of  the  river.  The  pumping  station  is  placed  at  the  upper  end  of  the 
city,  within  its  suburbs,  and  just  above  its  sewerage  influence. 

The  works  were  constructed  by  the  "  Compagnie  General  des  Eaux,"  and 
are  under  the  charge  and  direction  now  of  the  officers  of  that  Company. 

The  pumping-house  lies  within  200  feet  of  the  river.  Two  steam  engines 
work,  each,  two  single-acting  lifting  pumps.  The  engines  are  each  double  cyl- 
linder  engines,  with  a  walking-beam,  to  which  the  pump  rods  are  attached,  con- 
nected by  a  crank  with  a  large  fly-wheel.  The  two  pumps  of  the  one  engine 
have  each  an  interior  diameter  of  (0.38  metres)  15  inches,  with  (1  metre)  3  feet 
3  inches  stroke.  The  two  pumps  of  the  other  engine,  (0.44  metres)  17  inches 
diameter,  and  the  same  stroke. 

The  engines  are  said  to  average  18  revolutions  per  minute,  and  they  work  an 
average  of  12  to  14  hours  a  day.  The  smaller  engine  was  making  18 
strokes  at  the  time  of  my  visit,  and  the  larger  14  to  15  strokes.  They  have  been 
in  operation  since  1855 — 11  years — and  have  performed,  says  the  Engineer, 
very  satisfactorily. 

There  is  a  rising  main  from  each  engine  to  the  reservoirs  or  basins  already 
mentioned.  These  pipe  mains  are  each  (0.29  metres)  114  inches  diameter,  and 
about  (2  kilometres)  6,560  feet  in  length. 

The  record  kept  at  the  office  of  the  Company  of  the  daily  work  of  the  pump- 
ing engines  gave  an  average  daily  delivery  to  the  city,  during  March,  1866,  of 
5,770  metres  cubic,  equal  to  1,524,434  U.  S.  gallons.  This,  for  the  population 
given,  is  at  the  rate  of  about  13.6  gallons  per  head. 

There  are  two  sytems  of  pipes  in  the  streets  of  the  city — one  for  the  de- 
livery of  filtered  water  to  such  as  desire  it,  and  one  for  the  delivery  of  the  river 
water  in  its  natural  state.  Water  is  taken  into  the  houses  from  either  system, 
according  to  the  choice  of  the  proprietor,  but  the  public  fountains  are  only  sup- 

15 


134  NANTES   WATER   WORKS. 

plied  with  the  unfiltered  water.  There  are  no  fountains  supplied  with  the  61- 
tered  water. 

The  filtered  water  supplied  in  March  was  calculated  to  average  (400  metres 
cubic)  105,680  U.  S.  gallons  per  diem.  A  large  portion  of  the  unfiltered  water 
delivered  was  consumed  by  tha  public  buildings,  hospitals  and  fountains,  the  city 
having  a  claim  on  the  Water  Company  for  a  daily  delivery  to  the  extent  of  4,000 
cubic  metres  if  necessary. 

The  public  fountains  are  only  supplied  for  four  hours  each  day,  from 
noon  to  4  p.  M.  Within  these  hours  such  of  the  inhabitants  as  have  not  pipes 
within  their  dwellings  must  lay  in  their  store  of  water  for  24  hours.  The  usual 
liberality  arid  waste  which  obtains  in  other  French  cities  is  reduced  to  a  min- 
imum here.  This  will  to  some  extent  account  for  the  low  rate  of  con- 
sumption per  head.  A  small  portion  of  clarified  water  from  the  Loire,  is 
supplied  by  another  Company,  and  sold  about  the  streets  in  casks ;  but  as  the 
amount  from  this  source  does  not  exceed  50,000  gallons  per  day,  its  effect 
on  the  general  rate  per  head  is  very  small. 

The  reservoirs  or  basins  aforementioned  as  situated  130  feet  above  the 
pump  well  are  three  in  number.  They  are  open  basins  grouped  around  a 
central  covered  basin  or  tank  which  receives  the  filtered  water.  The  accom- 
panying sketch  (Plate  XXIII.)  shows  the  arrangement. 

The  basins  A  and  B  are  used  for  settling  basins,  and  the  river  water 
is  at  rest  alternately  in  the  one  or  the  other  from  12  to  18  hours  before 
being  passed  through  the  filtering  materials.  One  basin  can  be  filled  by  the 
pumping  engines  in  much  less  time  than  is  occupied  in  passing  the  other 
through  the  filter,  for  the  amount  of  filtered  water  consumed  in  the  city  is 
comparatively  small.  The  fountains  do  not  receive  it,  and  the  extra  price, 
but  more  especially  the  incompleteness  of  the  process,  probably  prevents  its 
more  general  use  by  householders. 

The  amount  of  filtered  water,  it  has  been  seen,  does  not  much  exceed 
one-fifteenth  of  the  total  supply  ;  but  the  amount  used  at  the  public  foun- 
tains, during  the  four  hours  of  their  service,  was  stated  to  exceed  one-half 
of  the  whole  supply.  These  statements  are  vague,  but  are  indicative  of  the 
system,  if  nothing  more.  I  give  them  as  received. 

The  filters  occupy  a  narrow  space  on  that  side  of  each  settling 
basin  which  is  proximate  to  the  covered  basin.  By  reference  to.the  accompany- 
ing sketch  it  will  be  seen  that  they  are  arranged  along  the  side  wall  referred  to 
in  groups  of  six;  two  groups  or  12  small  filters  to  each  settling  basin.  Each  se- 
parate filter  is  (1  metre)  3*  feet  square,  and  contains  about  3  feet  in  depth  of 
filtering  materials. 

The  river  water,  after  having  been  allowed  a  certain  time  to  settle  or  de- 


NANTES  WATER  WORKS.  135 

posit  its  heavier  sediment,  passes  through  these  filters  into  the  covered  tank, 
whence  it  passes  by  pipes  to  the  city. 

Each  of  these  settling  basins  holds  (1,800  cubic  metres)  475,000  U.  S.  gal- 
lons, or,  allowing  for  the  water  near  the  bottom  which  is  not  passed  to  the  city, 
each  basin  has  a  capacity  equal  to  one-third  of  the  city  consumption. 

The  filtering  materials  as  described  to  me  were  composed  of  broken  stone, 
pebbles,  sand,  and  sponge.  The  entire  materials  were  taken  out  once  a  month, 
cleansed,  and  replaced. 

The  materials  rest  in  each  case  upon  a  perforated  cast-iron  plate,  through 
which  the  water  passes  into  the  shallow  drain  below,  which  communicates  with 
all  the  six  boxes  of  the  group,  and  has  a  connection  with  the  filtered  water 
basin. 

Instead  of  sponge,  a  preparation  of  wool  is  often  used,  obtained  from  the 
workings  of  the  woollen  factories,  and  this  is  more  thorough  in  its  operation  on 
the  water  than  sponge.  They  are  never  used  mixed.  The  sponge  or  wool 
which  forms  the  surface  layer  of  the  filter,  is  covered  with  a  perforated  plate, 
and  compressed  by  means  of  a  screw.  The  top  of  the  box  or  compartment  is 
then  covered  by  a  water-tight  plate,  and  the  water  of  the  settling  basin  reaches 
the  filter  through  a  short  tube  in  the  centre  of  this  plate.  An  india-rubber 
tube  is  attached  to  the  central  hole,  and  carried  to  the  surface  of  the  water, 
where  it  is  held  in  suspension  by  an  india-rubber  ball.  By  this  means  the  water 
for  the  filter  is  always  drawn  from  the  surface  water  of  the  settling  basin. 

The  filters  seemed  to  be  on  too  small  a  scale,  and  the  clarification  effected 
at  this  station  arose  mainly,  at  the  time  of  my  visit,  from  the  process  of  settle- 
ment in  the  settling  basins ;  I  compared  the  water  of  the  settling  basin  which 
was  then  being  drawn  through  the  filter,  with  the  same  water  after  it  had  passed 
through  the  filter,  and  could  distinguish  no  difference.  The  settlement  had  not  , 
entirely  clarified  the  water,  though  it  had  improved  it ;  and  the  passage  through 
these  small  filters  had  produced  no  perceptible  change.  The  Altered  water  was 
not  limpid,  but  retained  the  slight  milky  hue  which  appeared  in  the  basin.  The 
river  water  at  this  time  was  but  slightly  turbid. 

The  settling  basins  are  cleansed  at  short  intervals,  by  flushing  off  about  2 
feet  of  the  bottom  water,  and  making  it  carry  the  accumulated  sediment  with 
it,  the  sediment  being  stirred  up  and  brushed  off  the  bottom  by  men  using 
sweeps  and  brooms. 

The  third  basin,  C,  shown  on  the  sketch,  is  not  in  any  way  connected  with 
the  filtering  apparatus  now,  but  forms  a  reserve  of  river  water,  holding,  when 
full,  (2,400  cubic  metres)  63,400  U.  S.  gallons,  or  half  a  day's  supply.  It  was  about 
half  full  at  the  time  of  my  visit.  At  midday,  when  the  public  fountains  are 
open,  it  is  always  drawn  down,  the  pumping  engines  not  being  competent  then 
to  meet  the  full  draft  on  the  city  pipes. 


136  NANTES   WATER   WORKS. 

Each  of  the  pipe  mains  from  the  engines  to  the  reservoirs  connects,  in  its 
passage  through  the  city,  with  the  pipe  distribution. 

We  were  informed  by  the  officials  that  the  want  of  a  large  reservoir  in  con- 
nection with  the  works  was  much  felt,  and  that  it  was  in  contemplation  to 
construct  one.  The  Engineer  who  planned  and  constructed  these  works, 
and  who  is  still  in  charge  of  them,  very  obligingly  showed  me  the  original 
plan  of  the  works,  and,  together  with  the  machinist,  communicated  frankly  the 
necessary  explanations.  Although  the  filtered  water,  at  the  time  of  my  visit, 
was  not  sufficiently  limpid  to  be  satisfactory,  I  was  informed  that  its  usual  con- 
dition was  unobjectionable. 


LYONS  WATER  WORKS.  137 


THE  FILTERING  GALLERIES  AND  BASKS  AT  LYONS, 


NATURAL    FILTERS. 

The  population  in  1866  was  variously  stated  to  be  300,000  to  315,000. 
The  water  supplied  to  the  city  of  Lyons  is  derived  mainly  from  the  river  Rhone. 
A  slight  difference  in  the  character  of  the  river  water  and  that  of  the  filtering 
galleries,  as  stated  by  the  chemists,  shows  that  some  water  from  springs  or 
sources  containing  a  larger  proportion  of  the  salts  of  lime  than  the  river  water 
mixes  with  the  underground  flow  from  which  the  filter  basins  and  galleries  are 
supplied.  The  difference  is  stated  by  Mr.  A..  Dumont,  the  Engineer,  to  be  2$ 
degrees  of  the  hydrometer  of  MM.  Boudron  and  Boudet.  The  increase  in  hard- 
ness in  this  case  is  so  slight  as  to  be  of  little  practical  importance. 

The  head  waters  of  the  Rhone  are  found  in  the  granite  regions  of  the 
Swiss  Alps,  whence  they  pass  into  and  through  the  Lake  of  Geneva.  Be- 
tween Geneva  and  Lyons  the  river  acquires  the  turbid  hue  which  marks  it  at  the 
latter  place,  and  from  the  calcareous  formations  through  which  it  passes  after 
leaving  the  Alps  it  probably  acquires  the  hardness  which  characterizes  it  at 
Lyons.  The  velocity  of  the  stream  iu  its  ordinary  stages  does  not  exceed  three 
miles  an  hour  at  Lyons,  since  small  steamers  ply  on  it  there  freely.  The  works 
for  the  supply  of  the  city  are  situated  in  the  narrow  gravel  plain  of  Petit  Bro- 
teau,  situated  on  the  right  bank  of  the  Rhone,  above  the  city  proper,  in  the 
small  suburb  of  the  Croix  Rousse. 

The  works  there  consist  of.  two  filter  galleries  and  two  filter  basins,  with 
one  engine-house  for  the  low-service  engines,  one  engine-house  for  the  high-ser- 
vice engines,  and  an  engine-house  for  a  small  auxiliary  engine  now  used  to  sup- 
ply a  small  reservoir  in  the  Jardin  des  Plantes  with  the  river  water  occasionally, 
when,  as  during  very  low  stages  of  the  river,  the  filtered  water  becomes  deficient 
in  quantity.  The  relative  positions  of  the  separate  works  are  shown  on  the 
accompanying  sketch.  (Plate  XXIV.) 

The  low-service  engines  deliver  their  water  into  a  low-service  reservoir  of 
10,000  cubic  metres  capacity  =  2, 641, 800  U.  S.  gallons,  situated  (its  bottom) 
45.70  metres,  or  150  feet,  above  -extreme  low  water  (1'etiage)  of  the  Rhone. 
The  high-service  engines  deliver  their  water  into  a  high-service  reservoir  of 
6,000  cubic  metres  (1,585,080  U.  S.  gallons)  capacity,  situated  94  metres,  or 
308  feet,  above  low  water. 


138  LYONS   WATER   WORKS. 

To  supply  the  small  district  of  Fourvieres,  situated  above  the  last-men- 
tioned reservoir,  a  small  pumping  engine,  placed  near  the  high-service  reservoir, 
pumps  the  water  for  this  highest  service  into  a  tower  55  metres,  180  feet  high, 
containing  the  necessary  stand-pipe  to  that  end.  In  the  low-service  engine- 
house  there  are  three  engines  of  the  Cornish  type,  each  of  the  same  power  (170 
horse).  In  the  original  arrangement,  one  of  these  engines  was  adapted  to  the 
high-service  duty,  one  to  the  low-service,  and  one  held  as  a  reserve,  and  made 
applicable  to  either.  They  are  all  three  applied  now  to  the  low-service  duty. 

The  pumps  are  plunger  pumps,  of  1  metre  (392  inches)  diameter,  and  2.50 
metres  (98  inches)  stroke,  each,  the  engines  making  ordinarily  7  strokes  per 
minute.  The  actual  delivery  of  the  pump  is  given  by  the  Engineer  as  1.80 
cubic  metres  (G3i  c.  feet)  per  stroke.  The  supply  of  the  city  at  present  requires 
about  20  hours'  work  per  diem,  two  engines  being  occupied,  and  one  always  in 
reserve. 

There  have  been  added,  within  the  last  two  years,  two  engines  for  the 
high-service  duty.  They  are  duplicates  in  plan,  and  not  of  the  Cornish  type. 
Each  engine  is  connected  with  a  fly-wheel.  The  pump  is  placed  directly  under 
the  steam  cylinder,  and  is  a  plunger  and  bucket  pump  ;  the  stroke  1.25  metres 
(49  inches)  ;  the  diameter  of  the  pump  barrel,  0.57  metres  (22^  inches).  The 
engines  made  15  to  16  revolutions  per  minute.  One  of  these  engines,  working 
about  eight  hours  daily,  maintains,  we  were  informed;  the  supply  for  the  high- 
service,  the  other  engine  being  in  reserve. 

The  daily  consumption  of  the  city  now  for  all  purposes,  I  infer  from  the 
work  of  the  pumping  engines  to  be  about  25,000  cubic  metres  (882,925  cubic 
feet),  or  about  22  U.  S.  gallons  per  head  daily.  At  the  lowest  stage  of  the 
river  the  delivery  of  the  filtering  works  does  not  exceed,  as  stated  to  me,  22,000 
cubic  metres  per  diem,  or  5,812,400  U.  S.  gallons.  This  gives  a  rate  per  head 
of  the  population  of  but  19  gallons  daily.  The  larger  quantity  of  22  gallons 
per  head  is  felt  to  be  insufficient.  In  comparing  this  with  American  and  English 
rates  of  consumption,  it  is  to  be  remembered  that  the  proportion  of  water  to  be 
expended  on  public  fountains  in  Lyons,  and  in  all  continental  cities  which  I  have 
visited,  very  much  exceeds  the  quantity  used  for  like  purposes  in  American  or 
English  cities.  The  rate  per  head  applicable  here  to  domestic  purposes  would 
hence  appear  to  be  unusually  low. 

The  supply  of  water  from  the  present  works  commenced  in  1856, -and  has 
been  since  continued  without  interruption.  The  water  delivered  into  the  city  is 
perfectly  clear,  and  it  is  obtained  in  this  state  here,  as  in  Toulouse,  by  taking 
advantage  of  what  is  called  the  natural  filter. 

The  narrow  plain  on  which  the  works  are  situated  consists  of  coarse  gravel 
and  sand,  very  pervious  to  any  waters  in  its  vicinity,  whether  they  percolate  into 
it  from  the  river  or  from  the  bluffs  to  the  north  of  it,  or  from  the  plain  above, 
of  which  it  forms  but  a  small  part.  In  this  gravelly  deposit  the  water  stands, 


LYONS  WATEU  WORKS.  139 

when  not  interfered  with,  at  about  the  same  level  as  the  river,  but  divested  of 
the  turbid  character  of  surface  streams,  and  clear  and  colorless.  This  body  of 
water  is  tapped  by  the  filtering  works  to  be  described,  and  can  always  be 
depended  on  within  certain  limits  for  the  invariability  of  its  results  as  respects 
freshness  and  limpidity. 

The  water  from  the  river  might  have  been  made  as  clear  by  an  artificial 
filter,  but  the  temperature  would  not  have  been  so  uniform  nor  so  satisfactory, 
and  the  daily  expenses  attending  the  manipulations  of  the  filtering  works  would, 
to  all  appearance,  have  been  greater.  Whether  the  first  cost  would  have  been 
more,  remains  yet  to  be  seen,  for  the  present  filtering  works  here  are  acknow- 
ledged to  be  insufficient  for  the  wants  of  the  city,  and  the  last-built  gallery  will 
evidently  have  to  be  extended. 

These  galleries  are  technically  called  filtering  galleries,  but  in  reality  they 
are  mere  receptacles  and  conduits  for  gathering  the  water  already  filtered  by  a 
natural  process.  They  serve  nothing  towards  the  filtration  of  the  water,  but 
only  towards  the  collection  of  a  portion  of  it,  and  its  transmission  to  the  pump- 
ing machines. 

The  first  gallery  constructed  is  marked  No.  1  on  the  accompanying  sketch. 
It  has  a  length  of  120  metres  (394  feet)  and  a  width  of  5  metres  (16.4  feet). 
There  are  no  openings  in  the  sides  for  the  collection  of  the  water,  but  only  on 
the  bottom,  which  is  entirely  open — the  coarse  gravel  being  all  along  visible. 
With  the  pumping  engines  at  work  the  water  in  this  gallery  stood  3  to  4  feet 
deep,  and  its  surface  stood  62  feet,  as  we  were  informed,  (2.0  metres)  below  the 
surface  water  of  the  Rhone,  situated  within  80  feet  of  the  gallery. 

At  a  few  points  the  water  boiled  up  in  small  springs  conveying  some  fine 
sand  with  it.  The  form  of  the  gallery  is  shown  on  the  accompanying  sketch. 
The  arch  is  covered  with  3  to  4  feet  of  earth,  but  the  gallery  is  well  ventilated 
and  well  lighted  by  a  number  of  uncovered  man-holes. 

This  I  understand  to  have  been  the  only  gallery  constructed  when  the 
works  were  opened  for  use  in  1856. 

The  water  obtained  from  this  gallery  having  proved  insufficient  in  quantity; 
a  square  basin  was  excavated  alongside  of  it,  marked  No.  2  on  the  sketch.  The 
bottom  of  this  basin  [was  carried  lower  than  the  bottom  of  the  gallery  No  1 
by  from  2  to  3  feet.  Its  waters,  however,  deliver  into  No.  1,  and  are  carried 
by  it  to  the  pump  well.  The  basin  is  vaulted  over  and  covered  with  earth  ;  a 
number  of  man-holes  give  it  light  and  ventilation. 

The  consumption  of  the  city  requiring  more  water  than  these  openings  pro- 
duced, a  second  basin  was  constructed  somewhat  larger  than  the  first ;  it  is 
marked  No.  3  on  the  sketch.  This  basin  is  vaulted  and  arranged  like  No.  2. 
Its  waters  deliver  also  into  the  gallery  No.  1.  It  was  completed  in  1859. 

But  the  construction  of  these  three  works  did  not  sufficiently  meet  the 


140 


LYONS   WATER   WORKS. 


wants  of  the  city,  the  consumption  of  water  by  the  inhabitants  having  probably 
much  exceeded  since  1856  the  consumption  which  had  prevailed  previously. 

A  new  gallery  was  consequently  determined  on,  of  larger  dimensions  than  the 
first,  and  placed  up  stream  along  the  bank  of  the  river,  breaking  into  new  ground, 
as  it  were,  and  collecting  from  the  same  gravel  plain  and  underflow  of  water, 
but  away  from  the  existing  works.  A  portion  of  this  new  gallery  was  con- 
structed and  opened  in  1863.  Where  the  Geneva  Railway  crosses  it,  its  dimen- 
sions are  reduced  from  10  metres  (33  feet)  in  width  to  2i  metres  (8  feet).  The 
portion  completed  is  therefore  in  two  pieces,  as  shown  on  the  sketch,  and  is  in 
all  100  metres  (328  feet)  in  length.  Its  continuation,  it  was  stated,  is  required 
now,  and  probably  will  soon  be  determined  on.  The  form  and  size  of  this  new 
gallery  are  shown  on  the  accompanying  sketch. 

At  the  lowest  stage  of  the  Rhone  (1'etiage)  its  surface  water  opposite  the 
works  stood  at  165  metres  (541  feet)  above  the  sea.  At  the  highest  flood  on 
record  (1862)  the  water  rose  to  169.51  (556  feet),  a  difference  of  15  feet  between 
extreme  low  and  extreme  high  water;  but  the  river  rarely  rises  within  5  feet  of 
the  above  mark. 

The  water  in  the  galleries  stood  during  our  visit,  according  to  the  scale 
attached  to  the  first  gallery,  at  0.85  metres  (21  feet)  below  its  zero  (1'etiage), 
or  164.15  metres  (538a  feet)  above  the  sea,  and  in  the  river,  by  our  information, 
it  stood  at  166.15  metres  (545  feet)  at  the  same  time,  the  difference  in  level 
being  62  feet. 

According  to  the  book  of  Mon.  Dumont,  the  Constructing  Engineer,  the  bot- 
tom or  filtering  areas  of  the  three  first  works  are  as  follows.  The  sketch  to 
which  I  have  referred  is  founded  on  the  one  given  in  his  book,  the  position  of 
the  new  engine-house  and  the  new  filtering  gallery  being  added  by  me.  Its 
basins  do  not  correspond  in  size  by  scale  with  the  figures  given  by  Mr.  Dumont, 
but  I  accept  these  figures  in  preference  to  dimensions  obtained  from  the  sketch. 
The  basins  being  full  of  water  rendered  it  impossible  for  me  to  verify  their  sizes. 


Metres, 
Square. 

Sq.  Feet. 

No.  1    on  the  sketch.    The  first  gallery  constructed,  opened  ) 
in  1856.     Area  of  its  open  gravel  bottom  j 

600 

6,454 

No.  2.  The  first  filtering  basin  built  to  increase  the  supply. 
Area  of  open  botton  

1,600 

17,200 

No.  3.  Second  filtering  basin,  completed  1859.     Area  of  its 
open  bottom  

2,168 

23,306 

No.  4.  The  new  filtering  gallery,  built  in  1863.     328  feet  long  ) 
(100  metres)  and  33  feet  wide  (10  metres).     Area  of  > 
gravel  bottom  .  .                                                                 j 

4,368 
1,000 

46,956 
10,750 

Total  filtering  area  at  this  date  

5368 

57706 

LYONS   WATER   WORKS.  141 

This  extent  of  area  for  22,000  cubic  metres  which  is  the  filtering  capacity  at 
low  water  of  the  river,  is  equivalent  to  100.7  U.  S.  gallons  per  diem  per  square 
foot  of  open  bottom.  But  as  the  shape  which  the  filtering  excavations  have  taken 
here  is  probably  not  the  best  for  a  maximum  delivery,  it  will  be  better  to  take 
the  new  gallery  by  itself  as  a  fairer  measure  of  the  amount  of  pure  water  obtain- 
able from  this  particular  deposit  by  underground  galleries.  An  experiment 
made  to  test  the  water  capability  of  the  new  gallery  gave,  we  were  informed,  a 
result  of  6,000  cubic  metres  in  24  hours.  The  bottom  area  being  1,000  metres 
square,  this  is  equivalent  to  147  U.  S.  gallons  per  square  foot  of  bottom. 

This  rate  of  delivery  is  very  much  less  than  that  of  the  new  filtering  gallery 
at  Toulouse.  The  velocity  of  the  stream  at  Toulouse,  held  baek  by  the  dam 
below,  did  not  exceed  from  one  to  Is  miles  an  hour,  while  here  it  appears  to  be 
from  2i  to  3  miles  an  hour.  This  would  not  sufficiently  account  for  the  differ- 
ence, which  must  be  influenced  by  some  difference  in  the  character  of  the  filter- 
ing material,  and  in  the  extent  and  volume  of  the  underground  flow. 

For  the  measures  of  the  water  capacities  of  such  works,  I  am  necessarily 
dependent  on  the  officials  in  charge,  and  although  the  data  have  undoubtedly 
been  communicated  with  much  frankness  and  good  faith,  it  is  not  in  the  nature 
of  such  things  that  the  experiments  on  which  they  are  founded,  hurriedly  as 
these  must  often  have  been  made,  should  always  be  correct. 

The  delivery  per  lineal  foot  of  this  gallery  is  by  the  same  experiment  4,833 
U.  S.  gallons  in  24  hours.  This  contrasts  less  dtsadvantageously  with  the  result 
of  the  new  Toulouse  gallery.  At  the  lowest  stage  of  the  river  the  water  in  the 
filtering  galleries  and  basins  is  reduced  2  feet  below  its  present  level,  and  it 
becomes  troublesome  then  to  work  the  pumping  engines,  except  by  intermitting 
their  action  and  allowing  the  water  to  accumulate  in  the  basins  and  rise  to  a 
convenient  height  in  the  pump  wells. 

Mr.  Dumont  states  in  his  book  that,  of  the  two  elements  required  in  certain 
proportions  for  a  free  delivery  of  water  in  a  filtering  gallery,  area  and  depth,  the 
last  is  very  much  the  most  important.  But  by  the  last  he  meant,  more  particu- 
larly, head,  or  difference  of  level  between  the  surface  water  of  the  underflow  in 
its  natural  state  and  that  water  when  drawn  down  in  basins,  or  otherwise,  by 
artificial  means.  This  will  be  readily  admitted  ;  but  it  is  at  the  same  time  con- 
ceded that  the  velocity  upwards  or  sideways  through  the  gravel  deposit  must 
not  be  so  great  as  to  carry  with  it  sand  into  the  basin,  or,  if  near  a  river,  it  must 
not  be  so  great  as  to  draw  water  from  that  river  in  a  turbid  condition.  The 
velocity  into  the  filter  basin  must  be  very  moderate  to  insure  safety  to  the  works, 
and  an  unvaried  purity  of  supply. 

With  the  view  of  increasing  the  supply  here  without  extending  the  filter 
basins,  and  of  testing,  too,  the  effect  of  drawing  down  the  water  in  the  filter 
basins  below  the  level  necessary  for  the  action  of  the  original  pumps,  a  small 

18 


UNIVERSITY  OF  C*f 
EttPARTMENT  OF  CIVIL  ENGINEER!?* 
BERKELEY.  CALIFORNIA* 


142  LYONS   WATER   WORKS. 

engine  was  built  at  the  suggestion  of  the  Engineer,  and  the  original  pump 
wells  being  cut  off  from  the  filter  works,  these  wells  were  temporarily  sup- 
plied by  this  new  engine.  By  this  action  the  water  in  the  filter  beds  was 
reduced  below  its  ordinary  level,  the  head  of  the  inflow  was  correspondingly 
increased,  and  the  rate  of  delivery  sensibly  augmented.  But  Ihis  increase  in 
velocity  of  the  inflow  through  the  gravel  proved  in  this  case  to  be  in  excess 
of  what  the  circumstances  admitted  of.  The  water  concentrated  itself  in 
springs,  and  brought  with  it  sand  in  sufficient  quantity  to  risk  the  under- 
mining of  the  vault  foundations.  The  maximum  for  the  situation  had  been 
overreached.  The  use  of  the  new  machine  was  therefore  stopped,  and  the 
works  restored  to  their  old  regime.  The  engine  is  now  used  as  an  auxiliary 
to  furnish  water  directly  from  the  river  to  the  reservoir  in  the  Jardin  des 
Plantes,  at  such  very  low  stages  of  the  river  as  inconveniently  reduce  the  sup- 
ply from  the  filters.  The  frank  statement  of  this  result,  which  I  have  gathered 
from  Mr.  Dumont's  report,  is  very  honorable  to  the  Engineer,  and  very  valu- 
able to  the  profession. 


TOULOUSE  WATER  WORKS.  143 


THE  FILTERING  GALLERIES  AT  TOULOUSE, 


NATURAL    FILTERS. 

The  population  of  Toulouse  is  stated  to  amount  to  100.000  souls  at  this 
date  (March,  1866). 

The  water  is  derived  from  the  Garonne,  indirectly,  by  means  of  subter- 
ranean galleries  situated  in  a  bank  of  gravel  on  the  left  bank  of  the  river. 

The  sources  of  the  Garonne  are  found  on  the  slopes  of  the  Pyrenees  chain 
of  mountains,  in  the  department  of  Ariege.  The  velocity  of  the  river  at  Tou- 
louse was  stated  to  me  to  average  ordinarily  1  metre  per  second,  or  about  2k 
miles  an  hour.  Immediately  opposite  the  filtering  ground  tha  velocity  dees  not  ex- 
ceed 2  miles  an  hour,  the  dam  erected  a  short  distance  below  having  modified 
importantly  the  current  there. 

The  bank  of  gravel  and  sand  in  which  the  galleries  have  been  constructed 
lies  within  the  city  limits,  but  in  what  may  be  called  the  suburbs  ;  the  dense 
portion  of  the  city  lies  below  this  point  as  regards  the  river,  and  upon  its  oppo- 
site bank. 

The  annexed  sketch  (Plate  XXV.)  will  show  the  position  of  the  filtering  gal- 
leries, and  of  the  pump-house  (Chateau  d'Eau),  upon  which  the  galleries  all  con- 
centrate. 

It  is  important  to  understand  the  relation  of  this  gravel  bank  to  the  lowest 
stage  of  the  Garonne,  and  to  its  flood  waters.  The  surface  water  of  the  Garonne 
at  its  lowest  stage  is  recorded  to  have  stood  433  feet  (132.09  metres)  above  the 
level  of  the  sea.  The  surface  of  the  gravel  bank  referred  to  is  on  an  average 
(136  metres)  446  feet  above  the  same  level,  or  about  13  feet  above  the  lowest 
stage  of  the  river.  The  river  floods  rarely  cover  this  bank  ;  in  long  intervals, 
however,  extreme  floods  set  over  it,  and  the  one  of  1832  rose  to  451 2  feet 
(137.69)  above  the  sea,  covering  this  gravel  meadow,  therefore,  with  some  5i 
feet  of  water.  . 

The  rise  of  the  river  in  ordinary  floods  may  be  taken  at  8  to  10  feet.  In 
the  highest  flood  on  record  referred  to  it  rose  to  18  feet  above  the  lowest  water 
of  the  river  opposite  to  the  present  pumping  engines. 

"  In  the  pump-house  there  are  two  breast  wheels  (163  feet  diameter  each, 


144  TOULOUSE    WATER   WORKS. 

exclusive  of  the  buckets,  and  5  feet  wide  each).  Each  wheel  works  four  plunger 
pumps  of  10$  inches  (0.27)  diameter  each,  and  3.80  feet  stroke.  All  the  pumps 
were  at  work  both  days  that  I  visited  the  pump-house,  and  according  to  their 
velocity  at  that  time  they  would  deliver  into  the  city  about  4,500  cubic  metres 
•  per  24  hours.  The  delivery  was  stated  to  me  to  average  5,000  cubic  metres  per 
diem  (176,585  cubic  feet),  equivalent  to  13^  U.  S.  gallons  per  head  of.  the  popu- 
lation. Each  set  of  four  pumps  delivers  its  water  into  a  vertical  pipe  of  10 
inches  diameter,  which  is  carried  up  the  pump-house  tower  to  a  height  of  66 
feet  above  ordinary  water  of  the  river.  At  this  height  the  waters  of  the  two  rising 
mains  are  delivered  into  -two  city  mains  of  the  same  diameter,  and  the  head  thus 
acquired  enables  the  numerous  fountains  to  be  well  supplied,  and  admits  of  the 
lower  stories  or  ground  floors  of  many  of  the  houses  receiving  the  water  into 
the  house.  In  this  last  respect,  Toulouse  is  at  present  very  imperfectly  accom- 
modated. There  is  no  reservoir  connected  with  the  pumps,  which  are,  there- 
fore, necessarily  kept  perpetually  at  work,  except  as  one  wheel  must  be  occa- 
sionally intermitted  for  repairs. 

These  pumps  have  be'en  in  use  since  1839.  The  new  pump-house  and 
engines  now  under  construction,  and  nearly  completed,  are  upon  a  scale  to 
admit  of  a  delivery  of  water  into  the  city  equivalent  to  a  rate  of  50  U.  S.  gal- 
lons per  head.  The  old  pumping  machines  will  be  altered  and  made  auxiliary 
to  the  new. 

The  new  works  include  a  sufficient  reservoir  to  defend  the  city  against  ac- 
cidents to  the  works,  and  to  admit  of  their  more  leisurely  repair  and  examina- 
tion. They  are  so  arranged  as  to  admit  of  the  water  being  received  into  the 
highest  stories  of  all  the  buildings.  These  new  works  are  being  constructed  in 
all  respects  most  substantially  and  thorough!}',  and  we  looked  over  their  details 
with  much  interest  and  satisfaction. 

The  form  and  size  of  the  gravel  bed  in  which  the  filtering  galleries  are 
situated  will  be  best  understood  by  reference  to  the  annexed  sketch.  In  this 
sketch  the  filtering  ground  is  colored  brown  to  enable  the  reader  to  understand 
its  extent,  but  upon  the  surface  it  is  covered  with  grass.  The  deposit  consists 
of  gravel  and  sand  of  different  degrees  of  fineness — its  surface,  however,  covered 
with  a  thick  bed  of  rich  soil.  The  whole  rests  upon'  a  compact  tufa  or  marl, 
and  as  will  be  seen  by  an  examination  of  the  sketch,  the  depth  at  which  any 
filtering  galleries  can  be  laid  is  limited  by  this  impervious  base.  The  surface 
of  the  marl  is  situated  here  about  12  feet  below  the  low  water  of  the  river. 

The  river  water  at  the  time  of  my  visit  did  not  carry  much  weight  of  sedi- 
ment, but  it  carried  sufficient  to  give  the  stream  a  dirty,  muddy  color. 

The  body  of  sand  and  gravel  referred  to  above,  so  much  of  it  as  lies  below 
the  level  of  the  water  in  the  river,  it  is  superfluous  to  say,  is  saturated  with 
water,  and  this  water,  although  evidently  derived  from  the  river  and  its  afflu- 


TOULOUSE  WATER  WORKS.  145 

cuts,  has  passed  through  such  a  width  or  depth  of  material  at  a  very  slow  velo- 
city, on  the  wide  plains  above,  as  to  have  deprived  it  entirely  of  the  matter  which 
gives  the  muddy  hue  to  the  stream.  In  the  filtering  galleries,  therefore,  it  is 
found  colorless  and  limpid.  Immediately  under  the  bed  of  the  stream,  or  in  too 
close  proximity  to  it.  this  result  would  not  probably  have  place.  The  first  filter 
gallery  or  drain  (C  D  on  the  sketch)  was  laid  at  a  distance  of  about  60  metres 
(197  feet)  from  the  bank.  The  bottom  is  situated  only  about  4  feet  below  the 
lowest  water  of  the  river.  The  form  is  square,  the  interior  width  1  foot  8 
inches,  the  height  3  feet.  The  side  walls  were  of  brick  laid  dry,  with  a  flagging 
stone  for  the  cover,  and  with  no  paving  on  the  bottom.  The  bricks  were  laid 
dry  and  the  bottom  left  uncovered,  that  the  water  might  have  free  access  to  the 
culvert.  The  inside  of  this  culvert  was  filled  up  with  small  stones,  probably  to 
,  prevent  the  side  walls,  which  were  not  in  mortar,  from  being  pressed  inwards. 
The  trench  in  which  the  culvert  was  laid  was  filled  up  again  with  the  materials 
taken  from  it.  A  coarse  gravel  was  found  at  the  bottom  of  the  trench  mixed 
with  flints.  The  gravel  became  finer  as  the  depth  lessened  from  the  surface, 
and  ended  in  a  fine  river  sand,  covered  at  present  with  from  2  to  3  feet  of  soil. 

The  length  of  this  first  filtering  culvert  is  056  feet  ;  it  is  said  to  have  deliv- 
ered at  all  times  clear  water  ;  but  the  quantity  was  soon  found  to  be  insufficient 
for  the  demands  of  the  city.  To  increase  the  supply,  a  second  filtering  arrange- 
ment was  projected  and  built,  differing  somewhat  in  character  frooi  the  first.  In 
this  second  case  eleven  wells  were  sunk  along  the  margin  of  the  river,  covering 
a  distance  of  300  feet  (g  h  on  the  plan).  They  were  carried  to  the  same  depth 
as  the  culvert,  and  steined  up  with  dry  brick.  The  wells  were  connected  together 
by  iron  pipes,  and  from  their  lower  terminus  a  connection  was  made  with  the 
pump  well  of  the  pump-house.  The  water  from  this  second  filter  turned  out 
bad,  and  it  has  consequently  been  for  some  time  in  disuse. 

A  third  filtering  culvert  was  constructed  on  the  same  plan  as  the  first,  but 
larger.  In  the  lower  part  of  its  course  it  is  situated  farther  from  the  river  than 
the  first  culvert,  and  in  the  upper  part  nearer  to  the  river  (c  ef  on  the  sketch)  ; 
the  length  was  given  me  as  1,476  feet  (450  metres).  Like  the  first,  it  has  always 
produced  good  and  clear  water. 

The  total  length  of  these  old  filtering  galleries  (excluding  the  wells  in  disuse) 
is  2,132  feet.  The  growing  wants  of  the  city  and  the  increase  of  its  population 
rendered  necessary  a  further  and  more  liberal  supply  of  water,  and  a  new  filter- 
ing gallery  has  been  constructed  within  the  last  two  years  in  the  same  bank  of 
gravel. 

It  will  be  convenient  to  note  here  the  water  capacity  of  the  old  galleries  so 
far  as  I  am  able  correctly  to  understand  it.  This  capacity  has  been  given  me  as 
equal  to  5,000  cubic  metres  per  diem,  and  I  judge  this  from  other  circumstances  to 
be  its  maximum.  ;jj°^  gives  a  rate  per  foot  per  diem  of  (2.345  metres  cubic)  620 


140  TOULOUSE   WATER   WORKS. 

U.  S.  gallons,  or  82.82  cubic  feet.  The  new  filtering  gallery  is  of  larger  dimen- 
sions than  the  others,  and  it  is  laid  lower  in  the  bed  of  gravel,  and,  consequently, 
has  a  greater  capacity  of  drainage  from  the  underground  reservoir  of  the  neigh- 
boring plain,  of  which  the  particular  gravel  bank  of  these  works  may  be  said  to 
form  a  part. 

It  difi'ers  in  other  respects  importantly  from  the  old  filtering  conduits.  Its 
contour  is  of  mortared  masonry  (in  this  case  beton)  of  sufficient  strength  to  defend 
it  from  the  outer  thrust  of  the  material  in  which  it  is  imbedded,  and  its  inte- 
rior is  not  filled  with  stones,  but  void — forming  thus  in  itself  a  considerable  re- 
servoir of  water.  The  water  finds  its  way  into  the  conduit  from  the  gravel 
deposit  in  which  it  lies,  in  part  by  small  earthenware  tubes  placed  on  both  sides 
of  the  gallery,  but  mainly  through  the  bottom,  which  is  left  (six-sevenths)  uu- 
paved  for  that  purpose,  and  where  the  clear  water  rises,  therefore,  from  the 
coarse  gravel  which  has  place  there. 

At  every  seventh  metre  a  buttress  is  thrown  across  of  one  metre  in  width, 
and  to  this  extent  (1-7)  the  bottom  is  impermeable.  The  surfaces  of  these  but- 
tresses, which  are  intended  to  defend  the  side  walls  against  movement  from  the 
back  thrust,  do  not  rise  above  the  prescribed  level  of  the  bottom  of  the  conduit. 

The  interior  height  of  the  new  conduit  is  8  feet  8  inches  (2.65  metres), 
the  width  7  feet  6  inches  (2.30  metres).  Its  form  and  position  is  shown  on  the 
annexed  sketches.  The  bottom  is  placed  at  129.45  metres  (424.6  feet)  above  the 
sea,  or  8  feet  7  inches  below  the  lowest  stage  of  the  river.  It  is  therefore  4^ 
feet  below  the  bottom  level  of  the  old  galleries.  The  present  length  of  the 
new  gallery  is  1,180  feet  (360  metres) ;  but  the  intention  is  to  extend  it  gradu- 
ally to  double  this  length,  or  more,  according  as  the  requirements  of  the  city 
may  demand  it.  An  experiment  made  by  the  Engineer  of  the  new  works,  Mons. 
Hepp,  indicated,  as  I  am  informed,  its  capacity  of  delivery  at  the  low  water  of 
the  river  to  equal  (10.000  cubic  metres)  2,642.000.  U.  S.  gallons  per  diem.  Its 
•extension  will,  it  is  supposed,  double  this  rate  of  delivery.  The  capacity  of  this 
new  gallery  at  low  water  is  therefore  equal  to  (2CT4o27°300)  2,462.  U.  S.  gallons  per 
foot  of  its  length,  while  that  of  the  small  conduits  was  but  620  gallons  per 
foot,  an  improvement  due  to  its  position  and  mode  of  construction  combined. 

It  will  be  observed  that  the  new  gallery  is  not  based  on  the  marl  or  tufa 
ypon  which  the  gravel  bed  rests,  but  is  kept  from  2  to  3  feet  above  it.  This 
has  been  done  to  permit  the  water  to  percolate  easily  into  the  gallery  from  the 
bottom,  where  it  is  expected  that  the  mass  of  the  water  will  enter  it,  rather  than 
from  the  side  tubes. 

With  the  present  rate  of  delivery  into  the  city  (5,000  cubic  metres  per  diem), 
1,320,900  U.  S.  gallons,  the  water  stands  now  in  the  new  gallery  (131.60 
metres)  2i  feet  below  the  ordinary  river  water.  During  the  experiment  refer- 
red to,  when  the  draft  from  the  gallery  was  at  the  rate  of  10,000  cubic  metres, 


TOULOUSE   WATER   WORKS.  147 

2,G41,180.  U.  S.  gallons,  it  stood  in  this  gallery,  according  to  my  notes,  at 
(128.15  metres)  4  feet  below  the  lowest  stage  of  the  river  water.  When  the 
new  pumps  are  completed  and  the  city  is  supplied  with  a. better  head  of  water, 
the  capacity  of  the  now  gallery  will  be  more  thoroughly  tested. 

I  have  given  above  the  experimental  rate  of  delivery  of  the  new  gallery  per 
lineal  foot.  -It  would  be  preferable  to  give  its  rate  per  square  foot  of  the  open 
bottom;  but  in  this  case  the  proportional  effect  of  the  side  pipes  is  difficult  to 
appreciate.  If  we  take  the  whole  width  and  length  of  the  gallery,  as  including 
a  sufficient  allowance  for  the  side  pipes,  and  to  that  add  the  bottom  area  of  the 
small  auxiliary  galleries,  we  shall  have  a  rate  of  delivery  at  low  water  of 
228  U.  S.  gallons  per  square  foot  of  open  bottom.  The  delivery  is  elsewhere 
given  in  a  pamphlet  published  at  Marseilles,  as  equal  to  27. 6  metres  cubic  per 
metre  courant,  or  2,223.  U.  S.  gallons  per  lineal  foot. 

The  dam  in  the  river  below  the  present  pump-house,  produces  compara- 
tively still  water  opposite  to  the  filter  ground,  and  must  encourage  that  kind  of 
sedimentary  deposit  there,  which  the  natural  current  of  these  rapid  mountain 
streams  does  not  admit  of,  except  in  eddies,  and  then  only  until  the  scouring 
operation  of  a  heavy  flood  clears  the  channel  of  such  accumulations.  But  when 
the  underground  material  of  the  plain,  for  some  distance  above,  consists  of  an 
equally  open  gravel,  it  can  be  of  little  consequence  that  the  river  bottom, 
within  the  influence  of  the  dam,  should  become  comparatively  water-tight.  The 
water  will,  in  any  case,  reach  the  filter  galleries  from  above,  and  from  a  some- 
what greater  distance,  arid  the  only  effect  would  be  to  reduce  the  rate  of  delivery 
somewhat,  and  perhaps  render  a  greater  length  of  gallery  necessary. 


148  MARSEILLES   WATER   WORKS. 


MARSEILLES  WATER  WORKS. 


MARCH,  18G6. 

The  supply  of  water  to  the  city  of  Marseilles  is  especially  noted  for  its 
abundance,  the  amount  at  present  passed  through  the  city  reaching  frequently, 
as  I  was  informed  by  the  Engineer,  a  rate  of  (550  litres)  145  U.  S.  gallons  per 
head  per  diem  ;  but  a  large  portion  of  this  water,  as  he  stated,  is  flushed  into 
the  harbor  to  carry  off  the  sediment  which  would  otherwise  accumulate  in  and 
choke  the  pipes.  The  water  passes  at  present  into  the  city  in  its  natural  state, 
and  without  filtration.  The  reasons  for  this  state  of  affairs  will  appear  here- 
after. 

The  population  of  Marseilles  is  given  as  250,000  in  18G4  ;  Mr.  Pascalcs,  the 
Engineer,  stated  it  at  300,000  at  this  date,  18G6,  and  I  find  it  elsewhere  stated 
at  the  same  figures. 

The  water  is  derived  from  the  river  Durance,  and  the  boldness  of  the  pro- 
ject will  be  admitted  when  it  is  stated  that  the  point  of  derivation  is  distant  62 
miles  from  Marseilles.  The  river  Durance  in  its  upper  reaches  is  a  rapid  moun- 
tain stream,  flowing  over  a  stony,  gravelly  bed. 

The  sources  of  the  river  are  widely  spread  upon  the  eastern  slopes  of  the 
lower  Alps. 

The  canal  of  supply  commences  on  the  Durance  near  the  bridge  of  Pertuis. 

In  the  construction  of  the  canal  the  city  had  two  purposes  in  view — the 
supply  of  the  city  with  water,  and  the  improvement  of  the  lands  in  the  vicinity 
of  Marseilles  by  irrigation.  The  amount  of  water  which  can  be  drawn  from  the 
river  Durance  at  the  lowest  stage  of  its  water  is  limited  to  5.75  cubic  metres 
(203  cubic  feet)  per  second;  but  the  ordinary  flow  into  the  canal  reaches  7  metres 
per  second  (159 1  millions  U.  S.  gallons  in  24  hours).  Of  this  amount  li  cubic 
metres  per  second  (34,240,320.  U.  S.  gallons)  is  considered  as  applicable  to  the 
city,  although  that  amount  is  not  used  there  at  present.  The  rest  is  available 
for  irrigation  and  water  power,  and  in  this  respect  has  been  a  source  of  great 
benefit  to  the  intermediate  country. 

The  Engineer  estimates  one-seventh  of  the  water  to  be  lost  by  evaporation 
and  filtration. 

The  canal  has  a  fall  of  6  inches  to  the  mile,  very  nearly  (0.30  metre  per 
kilometre),  and  its  dimensions  are  adapted  to  the  required  flow  mentioned  above. 


MARSEILLES   WATER   WORKS.  149 

There  is  no  navigation  upon  it.  It  is  open  throughout,  except  at  the  tunnels, 
which  are  numerous.  The  main  canal  is  carried  to  the  sea  below  Marseilles, 
delivering  its  surplus  waters  there. 

The  city  is  supplied  by  a  branch  3i  miles  in  length.  The  distance  from 
the  Durance  river  to  the  Marseilles  branch  is  682  miles,  and  to  the  filtering 
works  at  Longchamps,  as  already  stated,  62  miles.  The  waste  water  from  the 
fountains,  which  are  numerous,  and  from  the  flushing  of  the  pipes,  passes  into 
the  harbor  through  the  sewers,  which  are  thus  effectually  scoured.  The  health 
of  the  city  is  said  to  be  very  much  improved  since  the  introduction  of  this 
supply. 

The  Durance  river  is  represented  as  carrying  an  unusual  amount  of  sediment, 
and  as  presenting  in  this  respect  greater  difficulties,  as  regards  filtration,  than 
any  other  river  in  France.  The  average  amount  of  sediment  is  given  as  equal 
to  T-J-ir  of  its  volume,  but  this  is  probably  an  exaggeration  ;  Mons.  Bernard, 
Engineer  at  Aries,  gives  ^^  as  the  result  of  his  experiments  for  one  year. 

In  all  arrangements  for  filtering  turbid  river  water  by  artificial  means,  that 
portion  of  the  sediment  which  will  settle  in  comparatively  still  water  within  24 
hours  is  always  supposed  to  be  got  rid  off  before  placing  the  water  upon  the 
artificial  filter. 

The  means  provided  upon  this  canal  for.  clarify  ing  the  very  turbid  waters 
of  the  Durance  were  as  follows  : 

A  filter  bed  was  constructed  at  Longchamps,  in  the  upper  part  of  the  city, 
the  surface  of  which  is  (72  metres)  236  feet  above  tide  in  the  harbor. 

This  filter  bed  is  of  very  costly  construction,  as  will  be  seen  by  examination 
of  the  accompanying  plan  and  section.  (Plates  XXVI.  and  XXVII.)  The 
filtering  materials  rest  on  arches,  a  vaulted  chamber  of  like  dimensions  with  the 
filter  bed  being  constructed  below  it  for  the  reception  of  the  filtered  water. 
This  chamber  or  reservoir  will  hold  about  540,000.  U.  S.  gallons. 

The  filter  proper  is  composed  of  sand,  gravel,  and  stones,  in  about  the  fol- 
lowing proportions,  as  shown  on  the  accompanying  sketch  : 

1.  A  layer  of  small  stones  over  the  arches,  about 

8  inches  thick  at  the  top  of  the  arch 8  inches. 

2.  Broken  stone 3     " 

3.  Small  gravel 4     " 

4.  Coarse  sand  from  river 8     " 

5.  Ordinary  sand  of  "  Goudet " 3     " 

6.  Fine  sand  of  "  Montredon  " 12     " 

Total 38  inches. 

19 


150  MARSEILLES   WATER   WORKS. 

In  other  words,  the  filter  is  composed  of  two  feet  of  sand,  resting  on 
gravel  and  broken  stone. 

This  filter  is  said  to  have  operated  well  and  satisfactorily  while  the  water 
that  was  passed  upon  it  had  been  prepared  for  filtration  ;  when  this  ceased  to 
be  the  case,  it  became  rapidly  unserviceable.  When  I  saw  it  there  was  from  3 
to  4  inches  of  compact  mud  over  the  surface  of  the  sand,  and  it  had  not  been 
used,  except  as  a  reservoir  for  water,  for  two  years. 

It  is  vaulted  over  throughout,  and  therefore  not  very  conveniently  acces- 
sible for  cleansing  or  renewal.  The  filter  bed  is  in  two  divisions,  which  can  be 
used  together  or  separately,  as  may  be  desired.  -The  areas  are  as  follows, 
excluding  the  pillars  upon  which  the  arches  rest : 

Division  No.  1 47,613  square  feet. 

"     2 44,753 


" 


Total •   .      92,366  square  feet. 

Filtering  at  the  rate  of  90  U.  S.  gallons  (72  gallons  imperial)  to  the  square 
foot,  these  filters  would  be  competent  to  clarify  8,312,940  U.  S.  gallons  in  24 
hours,  or  half  this  quantity  with  but  one  in  use.  The  population  supplied  from 
them  did  not  probably  exceed  230,000  when  they  were  in  use,  which  would  give 
a  rate  of  36  U.  S.  gallons  per  head  with  both  filters  in  operation,  or  of  18  with 
but  one.  I  have  been  informed  that  this  filter  will  be  used  again  when  the 
means  proposed  to  be  provided  for  the  preparatory  removal  of  the  grosser  parts 
of  the  sediment  by  settlement  shall  be  completed  ;  but  it  is  obvious  that  for  a 
population  of  300,000,  increasing  from  year  to  year,  more  extended  arrangements 
somewhat  in  unison  with  the  general  project  would  be  required. 

When  these  filter  beds  were  in  use  they  were  cleansed  at  intervals  by 
reversing  the  movement  of  the  water  and  forcing  it  upwards  through  the  filtering 
material.  While  this  upward  movement  was  in  progress  the  surface  sand  of  the 
filter  was  raked  and  disturbed  by  laborers  with  suitable  tools,  to  facilitate  the 
removal  of  the  sedimentary  deposit.  The  turbid  water  thus  produced  was  run 
off  into  a  sewer.  The  water  used  for  this  purpose  must  have  been  the  clear 
water  of  the  reservoir  below.  When  water  is  in  such  abundance  as  in  this  case, 
the  amount  used  in  this  way  may  be  of  little  moment.  If  it  had  all  to  be  raised 
by  steam  power,  it  would  make  this  mode  of  cleansing  the  filters  a  very  costly 
one. 

To  get  rid  of  the  mass  of  the  sediment  of  the  river  by  settlement,  and  suf- 
ficiently prepare  the  water  for  filtration,  five  reservoirs  or  settling  basins  were 
constructed  on  the  line  of  the  canal,  in  certain  of  the  small  valleys  which  it 
crossed,  where  their  application  was  convenient  and  economical.  Dams  were 


MARSEILLES   WATER   WORKS.  151 

constructed  across  the  valleys  indicated,  sufficiently  high  to  bring  the  water  up 
to  the  canal  level,  and  through  these  dams,  pipes  and  sluices  were  provided  for 
flushing  off  the  sedimentary  deposits. 

The  water  of  the  canal  was  made  to  flow  into  one  end  of  each  of  these 
reservoirs,  and  passing  slowly  through  it,  the  reservoirs  being  deep,  it  parted 
with  a  portion  of  its  sediment  and  left  the  reservoir  at  the  other  end  in  a  less 
turbid  state,  returning  to  the  main  channel  there.  These  reservoirs,  or  settling 
basins,  for  such  was  their  use  and  intention,  were : 

1.  The   Ponseret  reservoir. 

2.  The  Garenne 

3.  The  Vallonbiere    " 

4.  The  Realtort 

5.  The  St.Marthe     " 

With  the  five  in  use,  a  superficial  area  of  220  acres  of  water  was  available 
for  settlement,  which,  including  the  effect  of  the  canal  itself,  must  have  been 
abundantly  sufficient  to  prepare  the  water  for  the  filter  beds  at  that  time. 

But  from  some  defect  in  the  construction  of  the  Realtort  dam,  this  reservoir, 
much  the  largest  (185  acres),  does  not  appear  to  have  been  long  in  use.  Of  the 
others,  the  Ponseret  basin  (No.  1)  is  the  only  one  now  serviceable,  and  this  has 
a  surface  area  of  but  2%  acres.  The  other  three,  for  reasons  growing  out  of  the 
difficulty  of,  or  neglect  in,  withdrawing  the  sediment,  have  been  allowed  to  fill 
up,  and  are  now  entirely  unserviceable.  A  considerable  quantity  of  sediment  is 
deposited  in  the  canal  itself,  which  is  cleansed  out  twice  a  year  ;  but  the  velo- 
city of  the  water  in  the  canal  maintains  that  water  in  a  very  turbid  state,  and  it 
consequently  reaches  the  filter  beds  now  in  a  condition  which  makes  their 
application  impracticable.  The  water  passes  into  the  pipes  of  the  city,  at 
present  in  its  dirty,  muddy  state,  to  the  great  dissatisfaction  of  the  inhabitants. 

Should  the  large  reservoir  of  the  Realtort  be  brought  into  use  again,  with 
the  means  of  scouring  it  proposed  by  the  Engineer,  Mr.  Pascales,  the  water  may 
again  be  rendered  fit  for  filtration.  Many  of  the  citizens  advocate  the  applica- 
tion of  the  natural  filter,  by  the  construction  of  subaqueous  galleries,  on  the  banks 
of  the  Durance,  and  it  remains  still  somewhat  uncertain  what  process  will  be 
adopted  to  render  the  water  tolerable.  Under  any  circumstances,  its  condition, 
in  summer,  after  being  exposed  for  62  miles  to  the  sun,  cannot  be  very  pala- 
table. 


152  GENOA  WATER  WORKS. 


GENOA  WATER  WORKS, 


GENOA,  March,  1866. 
NATURAL    FILTER. 

The  city  of  Genoa  is  supplied  with  water  from  two  separate  quarters,  the 
oldest  supply  being  derived  from  the  south  side  of  the  maritime  Alps  ;  the 
modern  works,  from  the  north  side.  The  first  is  still  in  charge  of  the  city 
authorities  ;  the  second  was  constructed  by,  and  is  operated  by,  the  Nicolay 
Water  Company,  under  a  special  concession  or  charter. 

The  construction  of  the  old  works  was  completed  in  1729.  The  water  in 
this  case  is  derived  from  the  river  Bisagno,  at  Stigliera,  by  damming  the  main 
stream  there  and  two  of  its  branches  ;  at  low  summer  water  the  amount  available 
does  not  exceed  from  80  to  100  litres  (say  3  cubic  feet)  per  second.  The  water 
is  conducted  to  the  city  in  a  small  masonry  conduit,  22  kilometres  in  length 
(13.6  miles).  The  width  of  the  conduit  is  0.80  metres  (2k  feet) ;  its  depth  varies. 
About  half  of  it  is  stated  to  be  covered,  the  rest  uncovered.  The  water  is  used 
at  one  place  outside  of  the  city  for  mill-power,  and  a  portion  of  it  in  the  same 
way  inside  of  the  city.  It  passes  through  the  city  as  a  covered  conduit,  deliver- 
ing its  water  on  either  side,  but  not  under  pressure.  There  are  no  filtering 
arrangements  connected  with  this  branch  of  the  water  supply. 

The  population  of  Genoa  is  variously  stated  at  from  150,000  to  165,000. 

The  new  works  of  the  Nicolay  Company  derive  their  water  from  the  valley 
of  the  river  Scrivia,  near  Busallo,  at  a  point  distant  (26  kilometres)  16  miles 
from  Genoa. 

The  river  Scrivia  has  its  source  in  the  northern  slopes  of  the  maritime  Alps. 
It  is  a  rapid  mountain  stream,  the  channel  at  Busallo  evidencing,  by  the  coarse- 
ness of  the  gravel  or  shingle  composing  it,  the  rapidity  of  the  current.  The 
water  is  gathered  from  underground  galleries  in  the  valley  of  the  Scrivia,  is  con- 
veyed thence  by  cast-iron  pipes  to  Genoa  without  exposure  anywhere,  and  is 
introduced  into  the  city  under  pressure  by  a  net-work  of  pipes,  whence  it  can 
be  carried  into  the  highest  stories  of  all  the  city  buildings.  In  all  respects  the 
scheme  is  more  complete  in  its  parts,  and  more  liberal  in  its  dimensions  and 
preparation  for  the  growth  of  this  thriving  seaport,  than  usually  obtains  in  con- 
tinental cities. 


,  GENOA  WATER  WORKS.  153 

The  Engineer  of  the  project  was  Guilio  Sardi  ;  the  Constructing  Engineer, 
Aleso.  Moschini,  and  the  President  of  the  Company,  Paulo  An.  Nicolay,  to  whom 
I  am  under  great  obligations  for  the  facilities  which  he  afforded  me  toward 
obtaining  access  to  the  galleries. 

The  accompanying  sketch  will  explain  the  position  of  these  galleries  with 
reference  to  the  river.  (Plate  XXVIII.) 

The  wide  bottom  of  gravel  over  which  the  river  flows  here  is,  as  well  as  I 
could  learn,  40  to  50  feet  in  depth,  except  in  the  immediate  channel  of  the 
river,  where  the  depth  does  not  exceed  30  feet.  It  rests  upon  an  irregular  bed 
of  compact  rock,  and  the  underground  flow  of  filtered  water  is  held  up  by  this 
rock.  This  underground  flow  is  doubtless  moving  down  the  valley,  which  has  a 
considerable  fall  here,  but  at  a  very  slow  velocity  as  compared  with  the  river, 
its  movement  being  impeded  by  the  body  of  sand  and  gravel  through  which  it 
percolates. 

The  side  walls  of  the  galleries,  which  tap  this  underground  flow,  are  carried 
down  to  the  rock  above  mentioned,  as  will  be  seen  by  the  cross-sections  given 
in  the  accompanying  sketch.  The  underground  flow  cannot,  therefore,  pass 
under  the  gallery.  Referring  particularly  to  that  portion  of  the  gallery  which 
underlies  the  bed  of  the  river  at  right  angles  to  its  course,  the  underground 
flow  is  dammed  to  a  certain  extent  by  the  position  of  this  gallery,  and  must 
rise  over  the  top  of  its  arch  in  its  course  down  stream.  The  galleries  are  built 
of  hydraulic  masonry,  and  the  water  enters  them  by  pipes  built  in  the  side  walls 
of  the  up-stream  side.  There  are  no  pipes  on  the  heavy  side  walls  of  the  down- 
stream side  of  the  galleries.  The  effect  of  this  damming  process  must  be  to 
increase  the  head  of  the  underground  flow  at  this  point,  and  to  that  extent  to 
increase  the  volume  of  water  delivering  through  the  side  pipes  into  the  gal- 
leries. 

At  the  points  m,  n,  and  q  on  the  sketch,  there  are  large  man-holes,  with 
stairs  for  descending  into  the  galleries.  These  man-holes  had  houses  over  them. 
When  I  descended,  in  March,  1866,  the  galleries  were  full,  and  the  water  stood 
some  feet  above  the  soffit  of  the  gallery  arch.  It  was  perfectly  clear  and  limpid, 
and  reached  the  city  through  the  pipes  in  the  same  state.  At  the  point  n 
there  are  sluices  established  in  the  gallery,  by  which  that  part  of  it  from  n 
to  r  can  be  separated  and  its  waters  cut  off  from  the  portion  south  of  n.  In 
high  stages  of  the  river  these  sluices  are  closed,  the  water  from  the  portion  of 
the  gallery  south  of  n  (580  feet  in  length)  being  then  sufficient  for  the  city 
supply.  The  shutting  of  the  sluices  at  such  times  is  said  to  relieve  the  lower 
southern  part  of  the  gallery,  situated  alongside  of  the  railroad  tunnel  there; 
from  the  superfluous  pressure  of  the  flood  waters,  and  from  any  risk  of  leakage 
into  that  tunnel. 

The  galleries  are  five  feet  in  width,  by  seven  to  eight  feet  in   height,  in 


154  GENOA   AVATER   WORKS. 

English  measures.  The  amount  of  water  derivable  from  these  galleries  much 
exceeds  the  amount  required  by  the  city  of  Genoa  now,  and  the  works  are, 
therefore,  in  a  condition  to  meet  liberally  the  growth  of  the  city  for  some  time 
to  come. 

The  water  consumption  of  Genoa  from  the  Nicolay  Works  was  stated  by 
Mr.  Nicolay  to  average  500  ounces  daily,  the  ounce  being  equivalent  to  800 
litres  (28.25  cubic  feet)  per  hour.  This  gives  a  rate  per  diem  of  about  10,000 
metres,  strictly  9,600,  which  is  equal  to  2,536,128.  U.  S.  gallons. 

If  we  take  the  population  at  160,000,  and  allow  three-fourths  of  it  to  be 
supplied  from  the  Nicolay  Works,  it  will  be  found  equal  to  15.8  U.  S.  gallons 
per  head  of  the  population  supplied.  An  experiment  made  during  a  very  low 
stage  of  the  river  in- 1865,  to  ascertain  the  minimum  capacity  of  the  filtering 
galleries,  gave  a  delivery  then  of  500  litres  per  second  (1,765.  c.  feet),  which  is 
equal  to  11,413,440.  U.  S.  gallons  in  24  hours.  This  minimum  rate  will  admit  of 
a  delivery  to  the  city  of  over  four  times  its  present  consumption. 

But  the  ordinary  delivering  capacities  of  these  galleries  must  approach  to 
double  its  minimum  rate,  and  when  it  shall  become  necessary,  the  minimum  rate 
can  be  largely  supplemented  by  providing  storage  reservoirs  for  accumulating 
the  surplus  water  of  the  more  abundant  months. 

The  galleries  being  1,780  feet  in  length,  the  minimum  capacity  is  equal  to 
(Li^l3>^o)==6,412.  U.  S.  gallons  per  lineal  foot  of  this  length.  This  is  a  greater 
rate  of  delivery  than  the  Toulouse  or  the  Lyons  galleries  indicated,  and  may  be 
referred,  in  part  at  least,  to  the  peculiar  mode  of  construction  across  the  channel 
of  the  stream.  Two  cast-iron  pipes,  of  171  inches  (45  centimetres)  diameter 
each,  convey  the  water  from  the  south  terminus  of  the  filtering  gallery,  along 
the  line  of  the  Turin  Railway  to  Genoa.  The  altitude  of  the  Scrivia  at  Busallo 
is  (360  metres)  1,181  feet  above  the  Mediterranean,  but  this  is  reduced  within  a 
mile  of  the  Scrivia  by  a  safety-valve  to  (280  metres)  918  feet.  At  Genoa  the 
pipe  distribution  is  divided  into  a  high-service  and  a  low-service.  The  pressure 
at  the  terminus  of  the  main  at  Genoa,  used  for  the  high-service,  indicated  320  feet 
and  at  the  terminus  of  the  low-service  main  203  feet.  Both  pipes  reached  Genoa 
under  the  same  pressure,  but  for  the  low-service  a  safety-valve,  wasting  a  certain 
amount  of  water,  reduced  the  pressure  as  indicated.  The  vault  in  which  these 
gauges  were  situated  was  estimated  to  be  about  30  feet  above  the  sea.  There 
are,  doubtless,  contrivances  along  the  line  for  relieving  the  pipes  of  their  super- 
abundant head,  and  reducing  it  to  the  manageable  pressure  which  we  find  exist- 
ing, as  above  stated,  at  their  entrance  to  the  city.  The  length  of  these  pipe 
conduits  has  been  already  stated  to  be  each  (26  kilometres)  16.15  miles.  A 
small  fraction  of  the  water  delivered  by  these  pipes  is  applied  in  the  city  to  mill- 
ing purposes ;  but  this  is  understood  to  be  in  addition  to  the  city  consumption 
proper,  as  given  above. 


LEGHORN  WATER  WORKS.  155 


LEGHORN  WATER  WORKS. 


LEOHOBN,  March,  1866. 
FILTERING  CISTERNS. 

Leghorn  is  supplied  with  water  from  a  number  of  springs  on  the  slopes  of 
the- low  mountain  range  of  Maggiore  and  Corbolone,  where  the  head  waters  of 
a  branch  of  the  river  Tora  take  their  rise. 

The  springs  are  brought  together  and  conducted  to  the  filter-house  or  cis- 
tern of  "  Pian  di  Rota"  by  a  small  covered  conduit  of  masonry.  The  length  of 
this  conduit  was  given  us  as  (14.05  kilometres)  8.73  miles.  The  water  space  in 
the  conduit  is  but  12  inches  in  width  and  17  inches  deep  (see  Plate  XXIX).  It 
is  conducted  over  the  valleys  upon  neat  bridges  of  masonry,  and  through  some 
ridges  by  roomy  tunnels.  The  amount  of  water  flowing  through  the  aqueduct 
(10th  March,  1866).  as  measured  that  day  in  one  of  the  tunnels,  was  568,760. 
U.  S.  gallons  in  24  hours.  In  low  summer  water,  according  to  the  Superintend- 
ing Engineer,  it  has  been  reduced  (June,  1864)  to  276,000.  U.  S.  gallons  per 
diem. 

The  population  in  1848  was  72,400;  it  is  stated  at  80,000  in  1861,  and  may 
be  safely  taken  at  82,000  now.  This,  for  the  amount  of  water  delivered  by  the 
aqueduct  at  this  date,  which  was  considered  an  average  of  the  spring  months, 
is  equal  to  but  about  7  U.  S.  gallons  per  head.  During  the  hot  summer  months 
the  supply  is  very  inadequate  to  the  requirements  of  the  population,  and  its 
increase  is  under  consideration. 

Leghorn  is  a  seaport,  and  there  is  very  little  irregularity  in  the  level  of  the 
streets,  which  are  generally  from  10  to  15  feet  above  the  water  of  the  Mediter- 
ranean. 

The  altitude  of  the  springs  above  the  sea  is  (256  metres)  840  feet. 

The  altitude  of  the  filtering-house  or  cistern  mentioned  above  is  (48 
metres)  157  feet  above  the  sea.  From  this  filter-house  the  water  is  conveyed  by 
a  9-inch  pipe  main  to  a  larger  cistern-house  within  the  city,  which  had  also 
apparently  a  process  of  filtering  in  contemplation,  and  is  curiously  divided  up 
towards  that  end  ;  no  filtration,  however,  is  attempted  there  now. 

Both  of  these  cistern-houses  are  tasteful  and  monumental,  as  specimens  of 
architecture,  but  costly  for  the  engineering  duties  required  of  them. 


156  LEGHORN  WATER  WORKS. 

The  length  of  the  pipe  main,  or  the  distance  of  the  two  cisterns  apart,  is 
(3,309  metres)  10,856  feet.  The  water  in  the  city  cistern  stands  ordinarily  about 
28  feet  above  the  sea.  The  pipe  mains  deliver  the  water  freely  into  the  city 
cistern,  unchecked  or  throttled  by  a  stopcock,  so  that  the  pressure  due  to  the 
altitude  of  the  outside  or  country  filter-house  is  not  applied  to  the  city,  the 
small  amount  of  water  at  present  available  probably  making  such  an  application 
impracticable. 

From  the  city  cistern,  water  is  distributed  by  pipes  to  the  numerous  foun- 
tains, and  it  is  to  these  fountains  that  the  inhabitants  go  or  send  for  water. 

A  supplementary  covered  cistern  in  another  part  of  the  city  acts  as  an  aid 
to  the  city  cistern  above  alluded  to,  in  increasing  the  small  provision  made  for 
the  storage  of  the  water  flowing  on  through  the  aqueduct  and  pipe  main  during 
the  night  hours. 

We  have,  then,  as  a  summary  of  the  works,  the  pipes  and  fountains  ex- 
cepted  : 

1st.  The  cluster  of  springs  situated  (17.36  kilometres)  10.78  miles  north- 
easterly from  the  city. 

2d.  The  aqueduct  from  the  springs  to  the  water  filter-house. 

3d.  The  principal  filter-house  or  cistern,  situated  (3,309  metres)  2.05  miles 
from  the  city.  (Plate  XXIX.) 

4th.  The  large  cistern  or  covered  reservoir  within  the  city  (Plate  XXX.), 
auxiliary  to  which  is  the  smaller  cistern  in  the  city,  increasing  simply  the 
reserve  of  water  in  store. 

The  Leghorn  Water  Works  have  been  spoken  of  as  possessing  very  simple 
and  efficient  arrangements  for  the  filtration  and  purification  of  the  water,  and  it 
was  therefore  that  I  was  desired  to  visit  them.  I  will  endeavor  to  describe 
what  these  arrangements  are. 

The  principal  filter-house  (Pian  di  Rota),  which  is  outside  of  the  city,  may 
be  called  the  outer  filter-house.  The  water  chamber  of  this  house  (see  the 
accompanying  Plate)  is  divided  into  seven  divisions. 

The  bottom  of  the  first  five  divisions  is  covered  with  a  filtering  material 
composed  of  gravel  and  charcoal  in  the  following  proportions  : 

1.  A  layer  of  coarse  gravel 8  inches. 

2.  A  layer  of  wood  charcoal 12     " 

3.  A  layer  of  coarse  gravel 8     " 

4.  A  layer  of  fine  gravel 12     " 

Total  thickness  .  40  inches. 


LEGHORN  WATER  WORKS.  157 

No  sand  is  used,  and  the  charcoal  is  not  laid  in  the  shape  of  powder,  but, 
as  described  to  me.  is  broken  to  about  the  size  of  very  large  gravel  and  so  laid  ; 
much  of  it,  however,  must  get  broken  up  smaller  during  the  manipulation  of 
laying  and  covering  it. 

In  the  sixth  chamber,  the  material  is  simply  gravel,  without  charcoal.  In 
the  seventh  chamber,  which  forms  the  receptacb  for  the  water  after  passing 
through  the  others,  there  is  no  filtering  material  on  the  bottom. 

The  first  division,  marked  a  in  the  Figure,  receives  the  water  from  the 
aqueduct.  The  water  cannot  pass  from  a  into  the  second  division  b,  except  by 
the  small  holes  provided  for  that  purpose  at  the  bottom  of  the  division  wall, 
and  to  reach  those  holes  it  must  pass  downwards  through  more  or  less  of  the 
filtering  material  in  a,  and  after  passing  through  the  holes  it  must  pass  upwards 
through  more  or  less  of  the  filtering  material  in  b,  to  fill  the  division  b. 

Thence  the  water  can  only  reach  to  fill  the  division  c  by  flowing  over  the 
top  of  the  wall  dividing  b  from  c,  there  being  no  holes  in  that  wall.  Having 
got  thus  into  c,  the  same  process  is  repeated  between  c  and  d,  the  water  after 
passing  through  holes  at  the  bottom  of  the  wall  dividing  c  from  d,  flowing  there-  . 
after  over  the  top  of  the  wall  dividing  d  from  e.  Thence  it  finds  its  way  through 
the  bottom  of  the  wall  dividing  e  from/,  and  after  filling  the  division/,  overflows 
into  the  final  division  g. 

At  the  time  of  my  visit  the  water  from  the  aqueduct  flowed  into  the  first 
division,  perfectly  clear.  There  were  fourteen  feet  in  depth  of  water  in  all  the 
divisions,  and  we  could  see  the  gravel  bottom  of  the  first  six,  and  the  paved 
bottom  of  the  seventh,  quite  distinctly.  Two  American  Engineers  accompanied 
me  in  my  visit  to  these  works,  Mr.  W.  H.  Talcott  and  Mr.  L.  B.  Ward,  and 
they  assisted  me  in  my  examination  of  the  water,  and  the  measurement  already 
referred  to  of  the  flow.  A  tumbler  of  water  taken  from  the  aqueduct  where  it 
flows  into  the  first  division  a,  was  compared  with  a  tumbler  of  water  from  the 
last  division  g,  and  we  could  not  distinguish  any  difference.  The  water  entered 
the  filter-house  clear,  and  there  was  consequently  no  duty  thrown  on  the  filter 
beds.  We  were  informed  by  the  attendant  in  charge,  that  the  filtering  material 
was  cleansed  or  changed  once  in  two  or  three  years  ;  the  last  cleansing  was 
after  an  interval  of  two  years.  This  account  was  corroborated  by  the  Engineer 
in  charge.  We  were  further  informed,  that  when  the  aqueduct  water  came 
down  turbid,  which  was  very  rare,  it  was  wasted,  by  means  shown  us,  into  the 
neighboring  valley,  and  not  passed  through  the  filter-house.  There  were  means 
provided,  besides,  for  connecting  it  with  the  city  main,  without  passing  it 
through  the  filter-house. 

As  two  and  a-half  feet  of  open  gravel  could  evidently  be  of  no  use  in  ren- 
dering turbid  water  clear,  the  material  relied  on  for  that  purpose  must  have 
been  the  charcoal,  the  gravel  being  used  only  to  keep  the  charcoal  in  place. 

20 


158  LEGHORN  WATER  WORKS. 

How  far  the  charcoal  would  have  answered  the  purpose  had  the  water  been 
turbid,  and  how  frequently  it  would  have  required,  in  that  case,  to  be  un- 
covered, and  more  or  less  renewed,  cannot  be  gathered  from  the  experience 
of  these  works,  for  we  were  informed  that  turbid  water  was  not  allowed  to 
be  passed  into  the  filter-house,  and  that  indeed  the  aqueduct  water,  coming 
from  a  collection  of  springs,  and  not  from  the  channel  of  a  stream,  was 
rarely  otherwise  than  clear.  The  works  were  not  considered,  by  those  in 
charge,  as  valuable,  or  as  necessary  for  nitration,  but  simply  as  monumental 
cisterns,  admitting  of  the  storage  of  a  certain  amount  of  water. 

The  area  or  superficies  of  the  filtering  material  in  the  six  divisions  referred 
to  is  about  7,450  square  feet. 

The  city  cistern  or  reservoir  (Plate  XXX.)  is  in  plan  divided  into  four  spaces. 
Into  two  of  these,  m  and  n.  the  main  pipe  from  the  country  reservoir  delivers 
its  water.  The  floors  of  divisions  m  and  n  are  covered  with  about  12  inches  of 
gravel,  as  is  the  bottom  of  the  small  square  division  p.  From  m  and  n  the  water 
reaches  p  by  holes  along  the  bottoms  of  the  respective  division  walls,  passing 
through  the  gravel  to  reach  these  holes,  and  to  fill  the  division  p.  From  p 
the  water  overflows  into  the  large  space  q,  and  thence  communicates  with  the 
city  fountains  by  a  system  of  cast-iron  pipes. 

There  is  no  charcoal  used  with  the  gravel  in  this  house,  and  although  the 
divisions  indicate  a  provision  for  filtration  in  case  it  should  have  been  necessary, 
no  operation  of  this  kind  is  necessary  now,  and  no  adequate  materials  for  that 
purpose  are  therefore  provided.  The  house,  therefore,  is  only  of  use  as  a  storage 
cistern. 

The  Engineer  in  charge,  Mons.  A.  Delia  Valle,  and  his  aid,  Mons.  Francesco 
Pelligrini,  very  obligingly  gave  us  access  to  the  works,  and  permitted  us  to  copy 
the  drawings  of  the  reservoir  houses.  The  Engineer  of  the  project,  Mons.  Paschal 
Poccianti,  of  Florence,  who  enjoyed  a  high  reputation  as  an  architect,  has  been 
some  time  dead. 


WAKEFIELD    WATEll   WORKS.  159 


WAKEFIELD  WATER  WORKS, 


ME.   THOMAS    SPENCER'S    PROCESS. 

I  visited  Wakeficld  in  August,  1868,  for  the  purpose  of  seeing  in  operation 
the  process  of  Mr.  Thomas  Spencer,  of  London,  for  the  purification  of  objection- 
able water.  Although  this  special  application  of  Mr.  Spencer  is  not  requisite 
upon  any  of  our  Western  rivers  now,  a  report  on  nitration  would  be  incomplete 
without  some  allusion  to  it.  The  population  of  Wakefield  was  given  me  at 
25,000.  The  supply  of  water  is  in  the  hands  of  a  Water  Company.  It  is  a  con- 
stant supply,  and  not  intermittent.  The  water  is  taken  from  the  river  Calder,  at 
a  point  about  a  mile  below  the  city.  This  river  rises  in  the  high  moor  lands,  west 
of  Halifax,  which  divide  Yorkshire  from  Lancashire.  In  its  course  it  receives 
the  sewerage  of  Halifax  and  many  small  places,  and  it  has  received  the  sewer- 
age of  Wakefield  before  reaching  the  point  whence  the  water  is  taken  by  the 
Water  Company ;  it  is  also  contaminated  by  the  refuse  waters  of  various  dyeing 
establishments  and  other  factories  situated  on  the  river.  On  the  other  hand,  the 
river  receives  at  Wakefield  the  lockage  water  of  a  canal  which  has  not  been 
subject  to  the  same  extent  of  pollution.  At  this  date  (13th  August,  1868)  the 
long  season  of  drought  and  the  low  state  of  the  stream  made  the  water  unusually 
objectionable.  A  tumblerful  taken  from  the  river  at  the  connection  of  the 
Company's  conduit  was  of  a  dark,  inky  hue,  and  slightly  offensive  to  the  smell. 
When  the  Company  established  its  works  here  some  twenty-three  years  back, 
the  river  water  was  comparatively  pure  ;  but  the  increase  of  the  population  resi- 
dent on  the  river  since  that  time,  and  the  growth  of  factories,  has  rendered  it 
entirely  unfit  for  domestic  use  in  its  natural  state.  This  condition  of  things  in- 
duced the  Company  four  years  ago  to  try  the  application  of  Mr.  Thos.  Spencer's 
mode  of  filtering  and  purifying  such  waters,  and  the  r.esult  has  been  wonderfully 
satisfactory. 

As  my  only  object  is  to  give  an  idea  of  the  materials  and  arrangement  of 
this  filter,  I  will  refer  very  briefly  to  the  general  arrangement  of  the  works:  On 
the  left  bank  of  the  river,  at  a  point  about  a  mile  below  Wakeneld,  there  are 
two  settling  reservoirs,  having  a  water  surface  of  six  acres.  The  water  is 
pumped  into  one  of  these,  and.  passes  thence  through  openings  in  the  division 


ICO  WAKEFIELD  WATER  WORKS. 

wall  into  the  other,  whence  it  is  drawn  by  a  conduit  to  the  pumps,  which  lift  it 
to  the  high  grounds  at  Fieldhead  where  the  filter  beds  are  situated.  The  water, 
in  its  course  through  these  two  settling  reservoirs,  has  deposited  the  greater 
portion  of  any  sedimentary  matter  held  in  suspension.  There  are  two  pumping 
engines  for  this  service,  each  of  them  operating  both  a  low-service  and  high-ser- 
vice pump  at  the  same  time. 

The  high  land  at  Fieldhead,  on  which  the  filter  beds  and  storage  reservoirs 
are  placed,  commands  by  at  least  fifty  feet  the  highest  ground  in  the  city.  It  is 
situated,  as  given  me,  150  feet  above  the  pumps  already  mentioned.  From  the 
pumping  engines  two  mains,  of  10  and  15  inches  diameter  respectively,  convey 
the  water  to  the  filters. 

There  are  four  filter  beds  at  Fieldhead,  and  two  small  storage  reservoirs. 

The  floor  of  the  filter  bed  is  concrete,  resting  on  a  layer  of  clay  puddle. 
Upon  this  floor  is  laid  a  series  of  small  drains  ;  in  the  case  of  the  first  two  filters, 
of  brick  •  in  the  case  of  the  two  last,  of  square  clay  pipes,  not  perforated 
all  over,  but  with  one  hole  in  the  centre  of  each,  over  which  a  cup  is  placed, 
perforated  with  a  dozen  small  holes  of  about  3-1 6th  inch  opening.  These  square 
pipes  are  in  three-feet  lengths,  the  size  inside  being  not  quite  4  by  5  inches ; 
they  have  sockets,  and  when  laid  constitute  a  series  of  collecting  drains  about 
five  feet  apart,  c,  c;  their  ends  on  either  side  opening  into  large  collecting  con- 
duits, whence  the  filtered  water  is  delivered  into  storage  reservoirs  in  communi- 
cation with  the  city  mains.  Each  of  the  clay  pipe  drains  is  connected  with  a 
vertical  air  pipe. 

Between  and  over  the  series  of  clay  pipe  drains  gravel  is  placed,  the  depth 
of  gravel  not  being  carried  to  more  than  three  inches  over  the  pipes.  Upon 
this  is  laid  17  inches  of  the  carbide  of  iron  mixed  with  fine  sand,  about  half  and 
half.  This  carbide  of  iron  forms  the  purifying  material  of  the  filter.  Over  the 
layer  of  carbide  of  iron  there  is  a  layer  of  fine  sand,  of  from  15  to  18  inches  in 
thickness.  The  sand,  as  I  understand  the  process,  is  mainly  depended  on  to 
clarify  the  water  from  anything  held  in  mechanical  suspension,  so  to  say,  but 
the  carbide  of  iron  destroys  the  noxious  gases  and  offensive  coloring  belonging 
to  any  water  contaminated  as  this  is  with  a  large  proportion  of  sewerage  and  of 
the  refuse  of  factories ;  and  this  it  is  said  to  do  usually  very  thoroughly,  for  the 
water  after  passing  through  the  filters  presents  nothing  offensive  to  the  taste  or 
smell,  and  is  used  unstintingly  by  the  citizens  ;  but  at  the  time  of  my  visit  the 
discoloration  was  not  perfect.  The  amount  of  water  used  in  this  hot  season,  and 
its  abnormal  character  in  the  river  as  regards  appearance,  had  evidently  taxed 
the  filters  beyond  their  capacity.  Of  the  four  filter  beds,  one  has  to  be  cleansed 
off  every  day,  removing  about  'I  inch  of  sand,  which  is  washed  and  cleansed  for 
renewal.  There  are,  therefore,  during  a  large  portion  of  the  24  hours,  but  three 
filter  beds'  in  use. 


WAKEFIELD  WATER  WORKS.  161 

The  walls  of  the  filters  are  vertical,  or  nearly  so.  In  the  absence  of  a 
correct  diagram  of  these,  which  I  could  not  obtain,  my  notes  give  the  ap- 
proximate area  of  the  four  filters  as  equal  to  16,400  square  feet;  three  of  them, 
therefore,  would  contain  about  12,300  square  feet. 

The  consumption  during  the  day  of  24  hours  was  stated  to  average  gene- 
rally 750,000  imperial  gallons.  Taking  the  average  day  rate  at  50,000  gallons 
per  hour,  we  have  a  flow  through  the  filters  of  four  gallons  per  square  foot  per 
hour,  which  would  not  be  considered  extreme  on  the  London  filters  ;  but  we 
are  to  consider,  that  a  very  slow  rate  of  filtration  may  be  necessary  here  as 
compared  with  the  Thames  or  the  sea,  to  enable  the  material  specially  pro- 
vided in  this  case  to  produce  its  effect  upon  a  water  so  very  much  more  objec- 
tionable than  these  others  as  regards  discoloration  and  exposure  to  offensive 
contaminations. 

The  carbide  of  iron,  which  forms  the  purifying  element  of  Mr.  Spencer's 
patent  process  of  filtration,  was  described  to  me  by  Dr.  Statter  as  being  pre- 
pared from  red  hematite  iron  ore,  by  mixing  that  ore  with  sawdust  in  equal 
portions  and  roasting  it  in  an  iron  retort.  The  result  is  crushed  to  the  size  of  fine 
gravel,  pea  size,  and  mixed  for  use  with  equal  parts  of  fine  sand.  It  costs,  de- 
livered at  the  works,  five  pounds  sterling  per  ton.  On  the  two  first  filters, 
it  has  been  in  use  without  change  or  addition  four  years,  and  is  said  not  to 
be  in  any  way  deteriorated.  The  filtered  water  is  drawn  into  two  small  stor- 
age reservoirs,  having  a  joint  capacity  of  2,750,000  imperial  gallons.  It  is 
thence  delivered  to  the  city  by  two  pipe  mains  of  12  and  15  inches  diameter 
respectively, 

I  am  indebted  to  Dr.  Statter,  the  Chairman  of  the  Water  Company,  for 
permission  to  visit  the  works. 

I  learned  from  Mr.  Filliter,  the  Engineer  of  the  Leeds  Water  Works,  that 
the  process  of  Mr.  Spencer  was  in  use  at  Southport,  and  also  at  Wisbeach,  ap- 
plied to  waters  that  are  not  contaminated  with  sewerage,  but  objectionable  in 
color  from  other  causes.  At  Wisbeach,  the  water  comes  from  a  moor  tract  of 
country,  and  is  discolored  by  peat ;  at  Southport,  the  water,  which  is  drawn  from 
wells,  is  tainted  with  iron  rust.  In  both  cases,  the  action  of  the  new  process  was 
said  to  be  successful  in  removing  the  objectionable  features. 


UNIVERSITY'  OF  CALIFORNIA 
«BP!AKT1V£ENT  OF  CIVIL 


BERKELEY,  CALIFORNIA1 


APPENDIX 


APPENDIX. 


OF     INSTRUCTIONS. 


OFFICE  OF  BOARD  OP  WATEB  COMMISSIONEES, 
ST.  Loois,  Dec.  Uth,  1865. 

JAMES  P.  KIRKWOOD,  Esq.,   Chief  Engineer. 

DEAR  SIR, — At  a  meeting  held  this  da}7  at  the  rooms  of  the  Commissioners, 
there  were  present  His  Hon.  the  Mayor,  J.  S.  Thomas ;  Philip  Wiegel,  and 
Dwight  Durkee,  President.  Mayor  Thomas  offered  the  following  resolution,  to 
wit :  « 

''Resolved,  That  James  P.  Kirkwood,  Esq.,  our  Chief  Engineer,  be  re- 
quested to  proceed  at  once  to  Europe,  and  there  inform  himself  in  regard  to 
the  best  process  in  use  for  the  clarifying  river  waters  used  for  the  supply  of 
cities,  whether  by  deposition  alone,  or  by  deposition  and  filtration  combined, 
making  such  an  examination  in  each  instance  as  will  enable  him  to  report  to 
this  Board  the  general  dimensions  and  special  characteristics  of  the  specific 
works  visited  by  him,  so  that  this  Board  may  be  able  to  appreciate  how  far  the 
same  mechanisms,  and  the  same  or  similar  combinations  of  materials,  are  likely 
to  be  adaptable  to  the  purifying  of  the  Mississippi  water  at  St.  Louis.  The 
following  cities  which  are  supplied  by  river  water,  and  which  possess  works  for 
the  cleansing  of  that  water  when  turbid,  are  indicated  as  points  to  be  visited,  to 
wit :  In  England — London,  Norwich,  Preston,  Nottingham,  and  Southampton  ; 
Scotland — Paisley  and  Perth  ;  in  Ireland — Dublin  ;  in  France — Lyons,  Tours, 
Toulouse.  Marseilles  ;  in  Germany — Berlin,  Hamburgh,  Brunswick  ;  in  Italy- 
Leghorn  ;  and  that  such  other  cities  not  above  mentioned  as  may  be  ascertained 
to  possess  works  of  this  class,  deserving  of  examination,  be  visited  also.  Pro- 
vided, however,  that  Mr.  Kirkwood  shall  so  arrange  his  movements  as  to  return 
to  St.  Louis  by  the  first  day  of  May,  1866,  at  the  furthest. 

21 


166  APPENDIX. 

"  Resolved,  That  Mr.  Kirkwood  be,  and  he  is  hereby,  empowered  to  employ 
such  assistance  or  interpreter  when  in  Europe,  and  particularly  where  foreign 
languages  are  spoken,  as  may  be  necessary  to  enable  him  to  get  all  the  infor- 
mation needed." 

Above  I  hand  you  copy  of  resolutions,  and,  to  enable  you  to  carry  them 
out,  I  enclose  herein  my  individual  check,  No.  30,009,  on  National  Bank  of 
North  America,  New  York,  for  $2,700,  which,  I  trust,  will  be  sufficient  for  the 
whole  trip. 

I  have  to  request  that  you  will  advise  me  of  the  receipt  of  this,  also  what 
day  you  sail,  and  any  other  particulars  you  choose  ;  and,  further,  that  you  will 
report  your  arrival  on  the  other  side,  with  such  observations  as  your  time  and 
inclination  will  permit.  With  the  hope  that  an  overruling  Providence  will  guide 
and  protect  you, 

I  remain  very  truly  yours, 

(Signed)  DWIGHT  DURKEE, 

President. 


APPENDIX. 


167 


Table  of  Equivalents  of  certain  Measures  mentioned  in  the  preceding  Descriptions. 


NAME  OF 

ITS  : 

EQUIVALENT 

IN 

. 

MEASURE. 

U.S. 

Gallons. 

Imp. 

Gallons. 

Litres. 

Cubic 
Feet. 

Cubic 
Metres. 

Cubic 

Inches. 

Pounds 
Avoirdupois. 

1  U.  S.  Gallon  

1. 

.833111 

3.785203 

.133681 

.0037852 

231. 

8  3388822 

1  Imp.  Gallon  .   . 

1.20032 

1. 

4.543457 

.160459 

0045434 

277  274 

10 

.2641866 

.220097 

1. 

.035317 

001 

61  0271 

2  204737 

1  Cub.  Foot  

7.480152 

6.232102 

28.315289 

1. 

028315 

1728 

62  37916 

1  Cub.  Metre  

264.18657 

220.096714 

1000. 

35.316609 

1. 

61027  0963 

2204  737 

1  Cub.  Inch  

036099 

Weight  of  a  cubic  inch  of  water,  English  standard,  .036065  Ibs.  avoir. ; 
U.  S.  standard,  .036099  Ibs.  avoir. ;  French  standard,  .036127  Ibs.  avoir. 

The  "Ordnance  Manual  of  the  U.  S.  Army,  1861,"  and  the  "Engineer's 
Pocket-Book,"  by  C.  H.  Haswell,  give  8.3388822  Ibs.  avoirdupois  as  the  weight 
(U.  S.  standard)  of  a  gallon  of  water,  from  which,  in  the  above  table,  the  weight 
of  a  cubic  foot  and  a  cubic  inch  are  calculated. 

The  same  works  give  61.0270963  cubic  inches  in  a  litre,  and  2.204737  Ibs. 
avoirdupois  as  the  weight  (French  standard)  of  the  same. 

The  "Engineer's  Pocket-Book,"  London,  1869,  and  "Beardmore's  Manual 
of  Hydrology,"  give  61.028  cubic  inches  in  a  litre,  and  a  weight  of  2.2055  Ibs. 
avoirdupois  for  the  same. 

"Beardmore's  Manual  of  Hydrology"  gives  10.003  Ibs.  avoirdupois  as  the 
weight  of  an  imperial  gallon.  "Agenda  Opperman,"  Paris,  1869,  gives 
4.543458  litres  in  an  imperial  gallon. 

All  of  the  above  works  give  277.274  cubic  inches  in  an  imperial  gallon,  as 
also  does  Francis,  in  his  "  Lowell  Hydraulic  Experiments." 


168  APPENDIX. 


LONDON  PUMPING  ENGINES, 


I  will  here  condense  in  a  tabular  form  some  of  the  information  in  regard 
to  pumping  engines  which  is  scattered  over  the  descriptions  of  the  London 
Works.  These  works  afford  fair  specimens  of  the  different  kinds  of  pumping 
engines  and  pumps  in  use  in  England  and  elsewhere.  The  greater  number  of 
them  are  found  to  give  very  satisfactory  results,  whether  as  regards  economy, 
endurance,  or  ease  of  action,  and  of  some  of  these  engines  it  may  safely  be  said 
that  they  have  not  been  anywhere  surpassed  in  these  respects. 

Two  types  of  pumping  engines  are  more  especially  esteemed  by  the 
generality  of  English  Hydraulic  Engineers,  opinions  being  much  divided  as  to 
which  should  have  the  preference.  These  are  :  the  single-acting  engine  with 
the  plunger  pump,  usually  called  the  Cornish  engine  ;  and  the  two-cylinder 
double-acting  engine,  with  the  plunger  and  bucket  pump,  which  may  be  called 
the  Simpson  engine.  The  fuel  economy  of  the  one  has  proved  to  be  as  good 
as  that  of  the  other  ;  but  the  cost  of  maintenance,  the  wear  and  tear,  we  have 
no  means  of  comparing.  The  current  expenses  of  some  of  the  Cornish  engines 
have  been  very  faithfully  given  by  the  Engineers  of  the  East  London  Water 
Works,  but  the  corresponding  expenses  of  the  double-cylinder  engines  have  not 
been  made  public.  We  are  rather  left  to  infer,  therefore,  that  the  cost  of  main- 
tenance and  repairs  is  in  favor  of  the  Cornish  engine.  The  double-cylinder 
engine  is  a  safer  engine,  the  crank  controlling  and  limiting  the  stroke,  which  in 
the  Cornish  engine  is  loose,  and  dependent  to  some  extent  on  the  watchfulness 
of  the  engine-man.  The  double-cylinder  engine  admits  of  a  higher  degree  of 
expansion  being  used  than  on  the  other,  with  much  less  strain  or  harshness 
of  action  on  the  machine.  In  this  respect  it  has  the  advantage  of  any  descrip- 
tion of  single-cylinder  engine,  an  advantage  which  renders  the  double-cylinder 
engine  specially  valuable  as  a  pumping  machine. 

The  following  are  the  results  of  test  trials  made  on  these  two  classes  of 
engines,  to  ascertain  the  rate  of  expenditure  of  fuel,  or  the  "duty,"  so  called. 

The  "  duty  "  in  England  for  pumping  engines  means  the  Ibs.  of  work  or 
Ibs.  of  load  raised  one  foot  high  by  one  cwt.  of  coal  (112  Ibs.). 

In  the   LTnited  States  it  has    been    referred  to  the   simpler    measure   of 


APPENDIX.  109 

100  Ibs.     The  English  results  have,  therefore,  been  reduced  to  meet  this  last 
unit. 

Ibs., 
raised  1  foot  high. 

The  four  double-cylinder  engines  at  Lambeth  were  tested  by  Mr. 
Joshua  Field  during  24  hours  without  stopping,  and  for  every 

100  Ibs.  of  coal  consumed  gave  a  duty  in  foot  Ibs.  of 86,665,075 

The  fuel  was  Welsh  coal  of  good  average  quality. 
The  New  River  engines  (double-cylinder),  tested  soon  after  com- 
pletion, gave  a  result  on  an  eight  hours'  run  of 100,892,847 

Using  Welsh  coal,  we  presume  of  best  quality. 
The  Chelsea  (double-cylinder)  engines,  tested  by  Mr.  Field  during 

24  hours,  gave  a  result  of 92,765,972 

Using  Welsh  coal. 
The  Chelsea  engines,   under  a  four  days'  trial  by  Mr.   Cowper 

(llth  to  15th  June,  1861),  gave  a  result  of 77,796,656 

The  three  tests  first  given  above,  and  all  short  tests,  are  of  little  account, 
except  as  affording  some  indication  of  the  capability  of  the  engine,  when 
compared  with  other  tests  of  about  the  same  duration. 

The  last-mentioned  test  of  four  days  approximates  more  nearly  to  the  ordi- 
nary work  of  these  engines  throughout  the  year,  as  stated  by  Mr.  Simpson,  the 
Engineer  of  the  Chelsea  and  Lambeth  Companies. 

The  "duty"  statistics  of  work  of  the  Cornish  engines  are  for  longer  periods, 
and  therefore  more  satisfactory. 

Ibs., 
raised  1  foot  high. 

During  a  five  days'  trial  of  the  80-inch  Cornish  engine  at  Old 
Ford,  by  Mr.  Wicksteed,  using  the  best  small  Newcastle  coal, 
the  result  was 86,737,739 

During  11 3  years'  work  of  the  same  engine,  using  ordinary  small 

Newcastle  coal,  the  steam  cut  off  at  1,  the  duty  was 69,093,852 

With  the  best  Newcastle  coal,  according  to  Mr.  Wicksteed,  it 

would  have  been 82,637,205 

The  Wicksteed  engine  (90-inch)  at  Old  Ford,  during  three  years 
work,  1848,  1849,  and  1850,  steam  cut  off  at  I,  gave  a 
result  of 73,079,032 

Mr.  Greaves,  the  Engineer  of  the  work,  stated  that,  using  the 
"commonest  coal  that  could  be  bought  in  1862,"  the  East 
London  Cornish  engines  gave  a  duty  result  of 62,500,000 

Mr.  Morris,  the  Engineer  of  the  Kent  Water  Works,  where,  how- 
ever, the  single-acting  engine  uses  a  different  form  of  pump 
from  the  Cornish  plunger,  stated  as  the  result  of  14  years'  ex- 


170  APPENDIX. 

Ibs., 
raised  1  loot  high. 

perience,  using  the  best  coal  at  25  shillings  per  ton,  that  these 

engines  had  shown  a  duty  of 75,892,222 

At  present  (1'863),  using  inferior  coal,  at  ten  shillings  per  ton, 

he  got  a  duty  of  but 66,964,000 

At  the  Kew  Bridge  station  of  the  Grand  Junction  Water  Works, 
there  are  five  Cornish  engines.  Mr.  Fraser  states  that  the 
usual  duty  maintained  there  "  throughout  the  year,"  using  small 
coal,  costing  13  shillings  per  ton,  is 65,178,477 

The  above  statements  show  sufficiently  that  the  double-cylinder  crank  and 
fly-wheel  engine  can  be  relied  on  to  afford  as  good  an  economy  of  fuel  as  the 
Cornish  engine  ;  the  short  trials  given  above  show  indeed  a  higher  ' '  duty  "  for 
the  double-cylinder  engine  than  for  the  Cornish  engines  ;  but  I  assume  that  for 
a  long  period  of  time,  and  using  the  same  quality  of  fuel,  they  would  not  exceed 
the  Cornish  rates. 

The  following  table  brings  together  the  leading  engines  of  the  London 
Works  (the  Kent  Works  excepted),  with  the  view  of  indicating  the  relation  of 
the  pump  load  to  that  of  the  cylinder.  This  is  a  mere  blocking  out,  so  to  say, 
of  the  question,  for  the  friction  of  the  engine  is  not  added,  as  it  should  be,  to 
give  the  actual  work  done  at  the  steam  end  ;  but  the  results  are  significant, 
nevertheless,  and  of  value,  we  think,  so  far  as  they  go.  The  addition  for  fric- 
tion would  have  been  in  most  cases  a  guess  which  the  reader  can  as  well  make 
for  himself.  The  data  on  which  the  table  is  founded  are  not  given  as  severely 
correct,  though  all  received  at  the  several  stations  from  the  persons  in  charge 
there,  and  from  personal  observation.  They  will  most  of  them  be  found,  I 
trust,  to  be  near  approximations.  Some  errors  have  evidently  crept  in,  and 
the  publication  of  the  table  may  lead  to  their  correction. 


APPENDIX. 


171 


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174  APPENDIX. 

The  following  table  in  regard  to  boilers  was  prepared  hi  the  hope  that  it 
would  expose  some  uniformity  of  opinion  and  practice  among  the  London 
Engineers,  as  respects  the  boiler  capacity  which  should  be  provided  for  a  given 
capacity  or  area  of  steam  piston.  The  batteries  of  all  the  engines  indicated  in 
this  table  are  composed  of  Cornish  boilers.  They  are  all  of  very  nearly  the 
same  general  dimensions,  and  they  are  all  worked  under  about  the  same  pres- 
sure of  steam. 

The  engines  too  are  mostly  single-acting  Cornish  engines  ;  the  rotary 
engines  given  in  the  table  are  served  by  the  same  class  of  boilers,  and  worked 
under  very  nearly  the  same  average  of  load  per  square  inch  of  piston.  Their 
action  is  more  rapid  in  the  proportion  say  of  8  to  12,  and  they  would  therefore 
use  more  steam  per  minute  for  any  unit  agreed  upon,  than  the  other  class  of 
engines.  By  referring  to  the  first  table  given  above,  the  reader  can  make  such 
correction  for  variations  in  velocity  as  his  judgment  may  dictate.  I  prefer  to 
give  this  table  in  its  crude  state,  without  attempting  the  nicety  of  correction 
due  to  the  various  modifying  influences  of  each  case. 

The  capacity  of  boiler  understood  here  refers  to  the  gross  size  of  the  boiler 
without  deduction  for  fire  space  or  flues  ;  these  last  bear  about  the  same  pro- 
portion to  each  other  in  each  case,  and  have 'therefore  been  disregarded.  The 
unit  at  the  steam  cylinder  to  which  the  boiler  capacity  is  applied,  has  been  taken 
as  one  square  foot  of  the  area  of  the  steam  piston.  This  unit  would  correctly 
represent  the  case,  were  the  velocities  of  the  pistons  of  the  different  engines 
the  same  ;  these  velocities,  however,  vary  even  in  the  same  class  of  engines,  and 
to  that  extent  the  proportionate  boiler  capacities  given  in  the  table  will  be  felt 
to  be  unsatisfactory.  But  as  the  variations  in  velocity  are  variations  of  practice 
rather  than  of  principle,  and  each  Cornish  pumping  engine  is  probably  designed 
with  reference  to  a  conventional  velocity  for  that  class  of  machine,  the  capacity 
of  boilers  provided  should  in  reality  bear  some  uniform  relation  to  the  engine 
as  it  may  be  supposed  to  have  been  designed,  rather  than  as  it  happens  to 
be  actuated.  This  kind  of  uniformity,  however,  is  not  found  to  exist.  The 
boiler  power  varies  considerably,  as  will  be  perceived  at  the  different  sta- 
tions, and  to  an  extent  that  is  not  easily  explainable. 

The  table  indicates  a  provision  of  boiler  of  from  100  to  140  cubic  feet 
of  boiler  space  to  1  square  foot  of  piston  area  for  the  single-acting  Cornish 
engines;  and  for  the  rotary  engines,  a  provision  of  from  200  to  250  cubic  feet 
of  boiler  space  for  each  square  foot  of  the  steam  piston  area.  The  rotary  en- 
gine, in  other  words,  should  have  at  least  double  the  boiler  capacity  per  square 
foot  of  its  piston  area,  which  would  be  requisite  in  the  single-acting  engine  ; 
the  steam  in  the  rotary  engine  being  used  on  both  sides  of  the  piston  and  the 
velocity  of  motion  being  usually  greater. 

The  first  Belleville  engine  (Cornish)  of  the  Jersey  Water  Works  was  pro- 


APPENDIX.  175 

vided  with  a  boiler  capacity  (4)  in  gross,  equivalent  to  150  cubic  feet  of  boiler 
space  to  each  square  foot  of  piston  area,  and  it  was  usually  worked  from  a 
boiler  capacity  (3)  equivalent  to  112  cubic  feet  of  boiler  space  to  the  square 
foot  of  piston  area.  At  this  time,  1869,  there  are  six  Cornish  boilers  to  two 
engines,  and  the  relations  of  these  give  112s  cubic  feet  of  boiler  provided  for 
each  square  foot  of  piston,  and  yet,  when  but  one  engine  is  in  use  it  is  usually 
served  now  by  four  boilers.  This  is  sufficiently  accounted  for  by  the  rate  at 
which  the  engine  is  worked  since  the  erection  of  a  stand-pipe, — 9  and  10  strokes 
per  minute,  as  compared  with  the  old  rate  of  6  and  7  strokes  per  minute. 


176 


APPENDIX. 


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INDEX. 


PAGE. 

Altona  Works — Filters  and  Settling  Basins 121 

"           "         Pumping  Engines 120 

Angers      "         Filtering  Galleries 128 

Berlin       "         Filters 113 

"            "          Pumping  Engines Ill 

Boilers  of  London  Works 174 

Chelsea  Works — Filters  and  Settling  Basins 27 

"            "     •    Pumping  Engines 30 

Dublin        "          Filters  and  Reservoir 103 

East  London  Works — Settling  Reservoirs 74 

"                "          Filters 75 

"                "          Pumping  Engines 77 

Edinburgh                     Reservoirs 97 

Filters 99 

Equivalents  of  different  Measures 167 

Filters — See  the  different  Works. 

Filtering  Galleries 108,  128,  139,  143,  and  152 

Genoa  Works — Filtering  Galleries 152 

Grand  Junction  Works — Filters  and  Settling  Basins 49 

"                  "         Pumping  Engines 51 

Hamburgh                          Settling  Reservoirs 116 

"         Pumping  Engines 118 

Lambeth                             Filters  and  Settling  Basins 35 

"         Pumping  Engines 36 

Leghorn                   "         Filtering  Cisterns 156 

Leicester                             Filters  and  Reservoir 82 

Liverpool                 "         Reservoirs ...  90 

Filters 92 

London                    "          21 

Lyons                       "         Filtering  Galleries ;  139 

Marseilles                           Reservoirs 151 

"         Filters..  149 


178  INDEX. 

PACE. 

Materials  of  Filters 9 

Nantes  Works — Filters  and  Settling  Basins 134 

New  River  Works — Settling  Reservoirs 63 

"              "         Filters 64 

"              "         Pumping  Engines • 67 

Perth          «    "         Filtering  Gallery. 108 

Pumping  Engines,  London •  •  *  • 168 

Settling  Reservoirs — See  London  Works,  etc. 

Southwark  and  Vauxhall  Works — Settling  Basins  and  Filters 42 

"                           "              "          Pumping  Engines .• 43 

St.  Louis — Proposed  Form  of  Filter •. 8 

Stand  Pipe .43,  52,  112,  118,  etc. 

Spencer's  Mode  of  Filtration 159 

Toulouse  Works — Filtering  Galleries •. 143 

Tours            "         Filtering  Canal 124 

Wakefield     "         Spencer's  Filters 159 

West  Middlesex  Works— Settling  Basins  and  Filters 57 

"                    "         Pumping  Engines 59 

York                        "         Filters  and  Settling  Basins.; 86 


ST..  mil  II 8 


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FILTER     BEDS       AND        RESERVOIRS 


PLATE  XII 


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OF  CIVIL  EN<SIMEERP?3 
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Section  tf?7nia?7i  fiJ/sr  at  AB 


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PLATE  XVI. 


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*  •  •  -v.  *. 


..-*».»»•  • 


UNIVERSITY  OF  C*t.1«>RNIA 

QttPARTMENT  OF  CIVTL  ENOJNEERIN1 

BERKEUEY.  CALIFORNIA 


SETTLING  BASINS    &    FILTERS 


4ELIO.  ENGR.&   PRI 


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PLATE    XXV. 


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PLATE  xxvi. 


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PLATE  XXVHI. 


SECTIONS 

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POSITION   OF  FILTERING   GALLERIES 

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THE    RIVER      SCRIViA 


BUSALLA 


ON 


FILTER   HOUSE 
OF  THE 


PL  Alt:   XXIX 


////•u//f///  ///e  centre 


PLATE  XXX. 


LEGHORN 

CITY  CISTERN 


.50 


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the  wiitrr  thrmfflh  1/ie  riittm 


7931286 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


